Dean Bertolatti

An application of ARIMA model to predict submicron particle concentrations from meteorological factors at a busy roadside in Hangzhou, China

In order to investigate the effect of meteorological factors on submicron particle (ultrafine particle (UFP) and particulate matter 1.0 (PM(1.0))) concentrations under busy traffic conditions, a model study was conducted in Hangzhou, a city with a rapid increase of on-road vehicle fleet in China. A statistical model, Autoregressive Integrated Moving Average (ARIMA), was used for this purpose. ARIMA results indicated that barometric pressure and wind velocity were anti-correlated and temperature and relative humidity were positively correlated with UFP number concentrations and PM(1.0) mass concentrations (p<0.05). These data suggest that meteorological factors are significant predictors in forecasting roadside atmospheric concentrations of submicron particles. The findings provide baseline information on the potential effect of meteorological factors on UFP and PM(1.0) levels on a busy viaduct with heavy traffic most of the day. This study also provides a framework that may be applied in future studies, with large scale time series data, to predict the impact of meteorological factors on submicron particle concentrations in fast-developing cities, in China.

Physicochemical and antimicrobial properties of citral and quercetin incorporated kafirin-based bioactive films

The aim of this study was to determine the physicochemical and antimicrobial properties of kafirin-based bioactive films incorporating the plant essential oil citral and the polyphenol quercetin. The addition of quercetin and citral both imparted a yellowish colour to the films. The tensile strength of films significantly decreased and elongation at break increased when citral was incorporated, whereas addition of quercetin did not alter these two film parameters. The rate of water vapour transmission of the films decreased with citral incorporation but the water vapour permeability was not affected by either citral or quercetin incorporation. Furthermore, incorporation of citral and quercetin significantly lowered the oxygen permeability of the films. Film made of kafirin alone had antimicrobial activity against Listeria monocytogenes, however, films incorporating citral exhibited the highest antimicrobial activity against Campylobacter jejuni, L. monocytogenes, and Pseudomonas fluorescens. These results suggest that kafirin-based films incorporating citral and quercetin have potential as bioactive packaging to improve food safety and quality.

Characterization of drug-resistant Staphylococcus aureus isolated from poultry processing plants in Western Australia

Poultry processing plants can provide a favourable environment for the survival and transmission of Staphylococcus aureus. It is known that infections due to antibiotic-resistant strains of S. aureus are an increasingly serious problem clinically and, since antibiotic exposure in food-animal species may lead to antibiotic-resistant bacteria, it is possible that processed poultry may constitute a reservoir for disseminating antibiotic-resistance into the community. The present study was undertaken to determine the prevalence of antimicrobial-resistant S. aureus in two poultry processing plants, and to characterize the isolates by antimicrobial susceptibility and chromosomal and plasmid DNA analysis. One hundred and twenty-six S. aureus were isolated from two poultry processing plants in Western Australia. All were sensitive to 14 of the 26 antimicrobials tested and all isolates were resistant to at least one antibiotic and one chemical marker, the prominent resistance combination being to penicillin and cadmium (89%). Forty-six (36.5%) of the isolates were resistant to six or more of the antimicrobial agents tested. Overall there were no consistent resistance patterns for the isolates and no consistent patterns were found between and within the two processing plants. There were 24 epidemiologically unrelated Sma1 contour-clamped homogeneous electric field (CHEF) groups and 17 different plasmid profiles detected among the isolates. All isolates were found to harbour from between one to seven plasmids. The majority of isolates carried at least one large plasmid (22-48 Kb), and one or more small plasmids (1-3 Kb). Some isolates with epidemiologically related CHEF patterns had similar plasmid profiles and resistance patterns.

Risk Factors for Leptospirosis Infection in Humans and Implications for Public Health Intervention in Indonesia and the Asia-Pacific Region

Prevention and control of leptospirosis require an understanding of risk factors. This review identifies risk factors associated with leptospirosis infection from countries in the Asia-Pacific region, and compares and contrasts these data with those available from Indonesia. MEDLINE, PubMed, and Scopus databases were used to search for relevant articles. Indonesian gray literature was searched for leptospirosis risk factor studies in Indonesia. A total of 34 articles were included in this review. The contrast between peer-reviewed publications and Indonesian gray literature revealed that the variety of risk factors associated with leptospirosis infection is region or area specific. The presence of skin wounds, the existence of rodents, especially rats, and activities related to contact with contaminated surface water are factors frequently reported to have significant association with leptospirosis infection in human in Indonesia and in other Asia-Pacific countries.

The effect of diesel exhaust exposure on blood-brain barrier integrity and function in a murine model

Epidemiological studies indicate that exposure to diesel exhaust (DE) is associated with vascular‐based disorders. To investigate the effect of DE on blood–brain barrier (BBB) function and integrity, 8‐week‐old BALB/c mice were randomized to DE in a cyclical treatment regimen over a 2‐week period. Functional integrity of BBB was determined by considering brain parenchymal abundance of IgG within the hippocampal formation and cortex at 6 h and 24 h intervals following final exposure treatment. Neurovascular inflammation was expressed as the abundance of glial fibrillar acidic protein. Two doses of DE were studied and compared to air‐only treated mice. Mice exposed to DE had substantially greater abundance of parenchymal IgG compared to control mice not exposed to DE. Increased parenchymal glial fibrillar acidic protein at 24 h post‐DE exposure suggested heightened neurovascular inflammation. Our findings are proof‐of‐concept that inhalation of DE can compromise BBB function and support the broader contention that DE exposure may contribute to neurovascular disease risk. Copyright

Utility of established cardiovascular disease risk score models for the 10-year prediction of disease outcomes in women

Cardiovascular disease (CVD) is a major cause of mortality globally. In absolute numbers, more women die from CVD than men do. CVD mortality risk differs between genders, reflecting the different distribution of modifiable risk factors and severity of CVD outcomes. This study reviews six established risk score models and their applicability to the female population. These models are assessed against two criteria: discrimination and calibration. Sensitivity, specificity and positive- and negative-predictive values are also examined. The risk score models are found to be limited in applicability, requiring recalibration beyond their study population. Relevant risk factors to predict CVD mortality for women, such as measures of obesity, physical activity, alcohol consumption, use of antihypertensive medication, chronic kidney disease and coronary artery calcium are generally not incorporated in these models.

Thermal inactivation of antimicrobial-resistant Gram-positive cocci in chicken meat: D and Z value determinations

Antimicrobial-resistance in Gram-positive bacteria is reported with increasing frequency in strains isolated from food animals. Their isolation from commercial poultry carcasses and meat products constitute a potential risk that resistant strains or resistance genes might spread to humans via the food chain. As bacterial inactivation by thermal process is a critical control point in the safe preparation of many ready-to-eat foods, it is important to determine the thermal resistance of these organisms. The present study was undertaken to investigate the thermal tolerance ( D and Z values) of antimicrobial-resistant, Gram-positive cocci in ground chicken meat. The antimicrobial-resistant, Gram-positive cocci for this study were isolated from two poultry processing plants in Western Australia. D and Z value data indicate that these isolates do not exhibit enhanced thermal resistant characteristics. The estimated lethal effect of the cooking process for chicken meat indicates that an internal temperature of 70°C for 2.1 min would provide a 7-log reduction of all cell suspensions tested.

Indoor Air Quality In Old And New Schools

It has been demonstrated that air pollution is associated with a wide variety of health impacts in humans, especially among the elderly and children. In this preliminary study the exposure levels of formaldehyde, particulate matter with a size less than 2.5 μm in diameter (PM2.5), number of ultra fine particles as well as indoor temperature and relative humidity were measured in six primary schools (three old and three new schools). A total of 20 classrooms were monitored twice a week, at the beginning and at the end of the week. The aim of this study was to compare exposure levels to selected indoor air pollutants between old and new schools located within the Perth metropolitan area, Western Australia. According to the findings the formaldehyde levels were higher than maximum permissible levels recommended by NHMRC in 45% of samples in old schools and 67% of the samples in new schools. In regards to PM2.5 concentrations, most samples were lower than the WHO guideline value of 25 μg/m (24 hour exposure). In terms of ultra fine particles, generally old schools had a higher number of ultrafine particles.

Prevalence of respiratory symptoms among children in rural Myanmar-disease burden assessment attributable to household biomass smoke

More than three billion people continue to rely on solid fuels as their primary source of domestic energy which is associated with elevated concentrations of indoor air pollutants and increased morbidity and mortality both in adults and children. In Myanmar, solid fuel including coal and biomass (such as dung, crop and charcoal) is the main source of energy used in households. A community-based pilot study was conducted in rural Myanmar with the aim to determine the prevalence of childhood respiratory symptoms in association with the use of biomass for cooking. A total of eighty households were recruited and monitored for exposure to particulate matter with size less than 2.5 μm in aerodynamic diameter (PM2.5) and carbon monoxide (CO). In addition, mothers were interviewed to understand their cooking habits, some house characteristics and children’s respiratory health. The study found that PM2.5 and CO were significant contributors for the prevalence of acute respiratory infections and trouble breathing among young children. House characteristics including mosquito coil, associated with children’s respiratory health. The study confirms that domestic environments in developing countries, like Myanmar, continue to have significant health impacts on children.

Cardiovascular disease risk score prediction models for women and its applicability to Asians

Purpose Although elevated cardiovascular disease (CVD) risk factors are associated with a higher risk of developing heart conditions across all ethnic groups, variations exist between groups in the distribution and association of risk factors, and also risk levels. This study assessed the 10-year predicted risk in a multiethnic cohort of women and compared the differences in risk between Asian and Caucasian women. Methods Information on demographics, medical conditions and treatment, smoking behavior, dietary behavior, and exercise patterns were collected. Physical measurements were also taken. The 10-year risk was calculated using the Framingham model, SCORE (Systematic COronary Risk Evaluation) risk chart for low risk and high risk regions, the general CVD, and simplified general CVD risk score models in 4,354 females aged 20–69 years with no heart disease, diabetes, or stroke at baseline from the third Australian Risk Factor Prevalence Study. Country of birth was used as a surrogate for ethnicity. Nonparametric statistics were used to compare risk levels between ethnic groups. Results Asian women generally had lower risk of CVD when compared to Caucasian women. The 10-year predicted risk was, however, similar between Asian and Australian women, for some models. These findings were consistent with Australian CVD prevalence. Conclusion In summary, ethnicity needs to be incorporated into CVD risk assessment. Australian standards used to quantify risk and treat women could be applied to Asians in the interim. The SCORE risk chart for low-risk regions and Framingham risk score model for incidence are recommended. The inclusion of other relevant risk variables such as obesity, poor diet/nutrition, and low levels of physical activity may improve risk estimation.