maxillary second molar with two palatal roots is a rare dental anatomy. the diagnosis and treatment of exceeded root may create challenge for clinicians. the authors discuss the retreatment of a maxillary second molar in which exceeded root was undiagnosed in previous treatment. the case report underlines the importance of complete knowledge about root canal morphology which achieved by careful...

Air pollution affects forest health through atmospheric deposition of acidic and nitrogen compounds and elevated levels of tropospheric ozone (O3). In 1985, a monitoring network was established across Europe and various research efforts have since been undertaken to define critical values. We measured atmospheric deposition of acidity and nitrogen as well as ambient levels of O3 on 12, 13, and ...

BACKGROUND The Botswana antiretroviral program began in 2002 and currently treats 42,000 patients, with a goal of treating 85,000 by 2009. The World Health Organization (WHO) has begun to implement a surveillance system for detecting transmitted resistance that exceeds a threshold of 5%. However, the WHO has not determined when this threshold will be reached. Here we model the Botswana governme...

Cadmium, lead and mercury contents in fish were studied. Fresh and frozen fish from 17 FAO localities were bought in Czech markets. Atomic absorption spectrometry technique was used for determination of cadmium, lead and mercury concentration. Ten samples exceeded the maximum permissible limit for mercury (0.5 mg/kg or 1 mg/kg for selected fish species) and three fish samples exceeded the maxim...

In 1997, seven sport fish species were sampled from seven popular fishing areas in San Francisco Bay. Mercury exceeded a human health screening value in 44 of 84 (52%) samples. All collected samples of leopard shark and striped bass exceeded the mercury screening value of 0.23 microg/g wet weight. PCBs exceeded the screening value in 51 of 72 (71%) samples. DDT, chlordane, and dieldrin, had low...