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Recent studies have shown that taconite workers may be at increased risk for mortality from lung cancer, mesothelioma, and cardiovascular diseases (CVD). The relationship between CVD and occupational dust exposures at these mines has not been well-studied. We conducted an air monitoring campaign to char-acterise fine aerosol concentrations at 91 locations across six taconite mines using direct-reading instruments to obtain measurements of mass concentrations (PM 2.5 or particles with aerodynamic diameter less than 2.5 mm, and respirable particulate matters or RPM), surface area (SA), particle number (PN), and particle size distributions. We fit a Bayesian model with an AR (1) (autoregressive order 1) correlation structure to estimate exposure while accounting for temporal correlation. The highest estimated geometric means (GMs) were observed in the pelletiz-ing and concentrating departments (pelletizing maintenance, ball-ing drum operator, and concentrator operator) for PM 2.5 and RPM. SA and PN generally had highest GMs in the pelletizing department that processed powder-like particles into iron pellets. Between-location variability estimates were generally higher than within-location, indicating larger differences in exposure levels at different locations between mines. Ranking between PM 2.5 and RPM generally agree with each other, whereas SA and PN were more consistent with each other, with some overlap with PM 2.5 and RPM. Differences in ranking these groups may have potential implication for occupational epidemiological studies that rely on exposure information to detect an exposure-response relationship. Future occupational epidemiological studies investigating fine aerosols exposures and health risk are encouraged to consider multiple metrics to see how they influence health outcomes risk.

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At least a dozen chemical compounds, commercially obtainable or under large-scale investigative use, are currently being recommended for the management of malaria. All of these, except quinacrine, pamaquine and the cinchona alkaloids, have been introduced during the past 5 to 10 years. Since the new drugs have appeared in medical literature under a variety of synonyms, including numbers and proprietary names, there is little wonder that much confusion prevails as to the identity and relative merits of the available antimalarial agents.This summary is not intended to be a critical review of all recent advances in the chemotherapy of malaria. Original references should be consulted for detailed descriptions of the variouis druigs and for evidence to support the generalizations which are necessary in a summary. Those familiar with the problems of making definitive comparisons of therapeutically active compounds will appreciate the need for many qualifying statements throughout the appraisals. As the characteristics of the predominant strains of malarial parasites in a given area may greatly influence the choice of drug regimens, dosage recommendations are intended to be merely representative. In all cases they refer to the oral dosage for an average adult.It is now accepted that the early development of sporozoite-induced malaria in man takes place in fixed-tissue cells, as has been demonstrated for Plasmodium vivax (1). It is further believed that persistent fixed-tissue forms, not yet actually demonstrated histologically, are responsible for the repeated relapses of P. vivax and P. malariae infections, but that such persistent forms do not occur in P. falciparum infections. In vivax and malariae malaria, drugs which are active only against the asexual erythrocytic parasites will stop acute attacks, or will suppress parasites and fever as long as administered, but will not prevent relapses. The actual relapse rates following Surgeon,

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