In Vitro Bond Strengths of Amalgam Added to Existing Amalgams

Freshly mixed amalgam added to existing amalgam restorations as a means of repair and allowed to set completely may be expected to join with nearly original strength, if sufficient condensation time and pressure are used.

Discharge after discharge: predicting surgical site infections after patients leave hospital

In this population-based retrospective cohort study, we examined the frequency, severity, and prediction of post-discharge surgical site infections (SSIs). We evaluated all patients admitted for their first elective surgical procedure in Ontario, Canada, between 1 April 2002 and 31 March 2008. Procedure and patient characteristics were derived from linked hospital, emergency room and physician claims databases within Canada's universal healthcare system. The 30 day risk of SSI was derived from the initial hospital admission, outpatient consultations, return emergency room visits and readmissions. The cohort included 622 683 patients, of whom 84 081 (13.5%) were diagnosed with SSI, and more than half (48 725) were diagnosed post-discharge. Post-discharge infections were associated with an increased risk of reoperation (odds ratio: 2.28; 95% confidence interval: 2.11-2.48), return emergency room visit (9.08; 8.89-9.27), and readmission (6.16; 5.98-6.35). The most common risk index predicted incremental increases in the risk of in-hospital SSI, but did not predict increases in the risk of post-discharge infection. Patients with post-discharge infections had baseline characteristics more akin to uninfected patients than patients with in-hospital infections. Predictors of post-discharge infection included shorter procedure duration, shorter length of stay, rural residence, alcoholism, diabetes and obesity. Post-discharge SSIs are frequent, severe, scattered over time and location, and hard to predict using common risk indices. They represent an important hidden burden in our healthcare system.

Myocardial infarction associated with recency of immigration to Ontario

BACKGROUND

New immigrants to North America exhibit lower rates of obesity and hypertension than their native-born counterparts. Whether this is reflected by a lower relative risk of acute myocardial infarction (AMI) is not known.

OBJECTIVE

To determine the risk of AMI among new immigrants compared to long-term residents, and, among those who develop AMI, their short- and long-term mortality rate.

DESIGN

Population-based, matched, retrospective cohort study.

SETTING

Entire province of Ontario, the most populated province in Canada, from 1 April 1995 to 31 March 2007.

PARTICIPANTS

A total of 965,829 new immigrants were matched to 3,272,393 long-term residents by year of birth, sex and geographic location.

MEASUREMENTS

The main study outcome was hospitalization with a most responsible diagnosis of AMI. Secondary study outcomes among those who sustained an AMI were in-hospital, 30-day and 1-year mortality.

RESULTS

The mean age of the participants at study entry was approximately 34 years. The incidence rate of AMI was 4.14 per 10,000 person-years among new immigrants and 6.61 per 10,000 person-years among long-term residents. After adjusting for age, income quintile, urban vs. rural residence, history of hypertension, diabetes mellitus and smoking and number of health insurance claims, the hazard ratio for AMI was 0.66 [95% confidence interval (CI): 0.63-0.69].

CONCLUSION

New immigrants appear to be at lower risk of AMI than long-term residents. This finding does not appear to be explained by the availability of health-care services or income level.

Eutrophication of lake waters in China: cost, causes, and control

Lake water eutrophication has become one of the most important factors impeding sustainable economic development in China. Knowledge of the current status of lake water eutrophication and determination of its mechanism are prerequisites to devising a sound solution to the problem. Based on reviewing the literature, this paper elaborates on the evolutional process and current state of shallow inland lake water eutrophication in China. The mechanism of lake water eutrophication is explored from nutrient sources. In light of the identified mechanism strategies are proposed to control and tackle lake water eutrophication. This review reveals that water eutrophication in most lakes was initiated in the 1980s when the national economy underwent rapid development. At present, the problem of water eutrophication is still serious, with frequent occurrence of damaging algal blooms, which have disrupted the normal supply of drinking water in shore cities. Each destructive bloom caused a direct economic loss valued at billions of yuan. Nonpoint pollution sources, namely, waste discharge from agricultural fields and nutrients released from floor deposits, are identified as the two major sources of nitrogen and phosphorus. Therefore, all control and rehabilitation measures of lake water eutrophication should target these nutrient sources. Biological measures are recommended to rehabilitate eutrophied lake waters and restore the lake ecosystem in order to bring the problem under control.