A multiyear workplace-monitoring program for refractory ceramic fibers: findings and conclusions

Results of a monitoring program carried out by members of the Refractory Ceramic Fibers Coalition as part of a Consent Agreement with the U.S. Environmental Protection Agency to measure workplace concentrations of refractory ceramic fiber (RCF) are presented. More than 700 personal monitoring samples were collected and analyzed annually from workers in RCF production and processing plants, as well as from those employed by customers/end users. The data indicate that (i) approximately 90% of time-weighted average (TWA) workplace concentrations are below the industry's recommended exposure guideline of 1 fiber per cubic centimeter TWA; (ii) workplace concentrations vary with functional job category; (iii) concentrations are approximately lognormally distributed; (iv) workplace concentrations are generally decreasing; (v) there are significant differences in workplace concentrations among plants operated by both RCF producers and customers; (vi) equations can be developed to interconvert data analyzed using different measurement techniques and counting rules; (vii) usage of respirators varies with the functional job category of the worker and the average fiber concentration; and (viii) workplace samples differ from those used in animal inhalation experiments in terms of the ratio of respirable particles to fibers.     

The effect of a carbonated beverage on the wear of human enamel and dental ceramics

Ochratoxins, of which ochratoxin A (OA) is the most prevalent, are secondary fungal metabolites of some toxigenic species of Aspergillus and Penicillium. OA has been shown to be nephrotoxic, hepatotoxic, teratogenic, carcinogenic and immunosuppressive. The natural occurrence of OA in food and feed stuffs is widespread, especially in temperate areas such as Canada, Denmark, Germany, Sweden and the United Kingdom, and detectable amounts were even found in randomly collected human milk samples in Germany, Sweden and Italy. Of greatest concern in humans is its implicated role in an irreversible and fatal kidney disease referred to as Balkan Endemic Nephropathy. The mean dietary intake for humans in the European Union was found to be in the range of 1 to 2 ng/kg bw/day. Compared with the Provisional Tolerable Daily Intake (PTDI) proposed by the WHO of 16 ng OA/kg bw/day for humans, the average OA intake in Europe seems to be rather low. The main contributor to the OA intake in humans are cereals and cereal products, other possible contributors are coffee, beer, pork, products containing pig blood/plasma, pulses and spices. Only very few countries have regulations for OA in food and feed products. Based on the current literature, the mechanisms involved in the toxicity of OA indicate three major effects: (1) inhibition of mitochondrial respiration correlated with a depletion of ATP; (2) inhibition of tRNA-synthetase accompanied by a reduced protein synthesis; and (3) enhanced lipid peroxidation. Generation of free radicals and lipid peroxidation as an important mode of action of OA in vitro and in vivo is discussed in detail, as well as counteracting effects of dietary antioxidants.     

Power and gender: violence and affection experienced by children in Barbados, West Indies

Discourses on violence conceptualize the phenomenon as a property of (1) individuals, (2) social circumstances, and (3) social relationships. Rigorous comparative tests fail to support the first and second hypotheses. Survey data collected in 1990 from a national random sample of 407 men and women aged twenty to forty-five from the West Indian island of Barbados indicate that one of four experienced physical and emotional violence as children. Boys and girls were equally likely to be abused by both mothers (or other female caregivers) and fathers (or other male caregivers); stepparents were no more likely to treat children violently than were biological parents. However, the presence of a stepfather increased the likelihood that women battered their daughters and decreased the likelihood that women battered their sons. In general, powerful women protected their children from violence, treated them affectionately, and elicited affection for them from their men. The probability that a son experienced an affectionate relationship with a biological father rose with the length of time the two lived together, but only for sons with powerful mothers. By contrast, men battered powerless women and the children of powerless women. Powerless women battered their own children.