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Increasingly stringent particulate matter (PM) emission standards have brought forth engine design improvements, cleaner-burning fuels, and aftertreatment technologies. Reductions in tailpipe PM mass have concomitantly reduced accumulation-mode particle emissions. However, some strategies promote the emission of nucleation-mode particles, which are typically quantified on a number (PN) basis. We previously demonstrated that PN emissions from heavy-duty diesel vehicles equipped with various aftertreatment systems were inversely correlated, and gravimetric PM mass was positively correlated, with two in vitro assays. This present work expands on the analysis of PM mass and PN with in vitro assays to also include four additional PM metrics: suspended PM mass, active particle surface area, aggregate particle surface area, and accumulation-mode particle number. This new analysis shows that like gravimetric PM mass, suspended particle mass and accumulation mode particle number are well correlated with dithiothreitol consumption rate (DTT) and macrophage reactive oxygen species consumption rate (ROS) assays (R 2 = 0.61–0.96). Data suggest that PM mass emissions dominated by nucleation-mode particles induce equal or slightly greater toxicity compared to PM mass dominated by accumulation-mode particles. Data also show that among all PM metrics, those used for regulating PM in the United States and Europe, namely gravimetric mass and solid PN are overall most correlated with in vitro toxicity. Moreover, continued exploration of alternative, low-cost, and more appropriate PM metrics is warranted to better understand the reproducibility of these findings on other engine applications, fuel types, and aftertreatment platforms. • Water soluble organic (WSOC) content in PM showed excellent agreement with DTT response. • PM mass and solid particle number metric showed the best correlations with toxicity metrics. • Mass metric accounted for contribution of nucleation mode to toxicity most appropriately compared to other metrics considered in the study. [ABSTRACT FROM AUTHOR]

The PSA screening for 25 years in America is the biggest cohort study in a field of public health.27 We should realize not only the significance of the early diagnosis and treatment of PCa, but also the dramatic decrease in PCaMR from 2002 to 2008. The data from the IARC were especially noteworthy.Moreover, the patients with highly aggressive PCa, who account for more than 30% of all PCa patients, could only be diagnosed earlier by PSA screening. The patients would thus gain the opportunity for earlier treatment and would have a prolonged, higher quality life-span. However, the complications of interventional treatments, including biopsy,radical prostatectomy and/or radiation therapy,will become more avoidable in the near future.According to the supporting evidence for the decrease in PCa mortality in PSA screening, we strongly hope that the USPSTF changes the 'D' recommendation for PSA screening.

We have analysed the reasons for the low reported incidence of prostate cancer in China and argue for early diagnosis and treatment of this disease. According to the 2002 database of the International Agency for Research on Cancer (IARC), the age-standardized incidence of prostate cancer in China is 1.6/10(5) person years (PY), with a mortality rate of 1.0/10(5) PY and mortality-to-incidence rate ratio (MR/IR) = 0.63. The MR/IR ratio of prostate cancer in China was found to be higher than the average in Asia (MR/IR = 0.57) and much higher than that in North America (MR/IR = 0.13). These data indicate that in China most prostate cancers were in the advanced stages at the time of diagnosis, and that patients had a short survival time thereafter. In 2004, Stamey et al. reported a retrospective American study of prostate cancer for the years 1983-2003. It was shown that most cases of prostate cancer detected by prostate-specific antigen (PSA) screening were in the advanced stage at the start of this 20-year period. These early follow-up data are quite similar to the results obtained from mass PSA screening of elderly men in Changchun, China. However, after the American programmes for early diagnosis and treatment of prostate cancer were accepted, tumours were diagnosed at earlier stages. On the basis of these findings, mass screening should be performed in the whole of China using serum PSA to facilitate early diagnosis and treatment of prostate cancer.