BACKGROUND To estimate a threshold limit value for a compound known to have harmful health effects, an 'elbow' threshold model is usually applied. We are interested on non-parametric flexible alternatives. METHODS We describe how a step function model fitted by isotonic regression can be used to estimate threshold limit values. This method returns a set of candidate locations, and we discuss ...

background: many studies have been conducted to assess the indoor air quality (iaq) of buildings throughout the world because it is closely related to comfort, safety and work productivity of occupants. however, there is still lack of available literature about iaq in tropical buildings that apply radiant cooling systems in conditioning the indoor air. methods: this paper reports the results ob...

A continuous-wave, mid-infrared, distributed feedback , interband cascade laser was used to detect and quantify formaldehyde (H 2 CO) using off-axis, integrated cavity output spectroscopy in gas mixtures containing ≈ 1–25 parts in 10 6 by volume (ppmV) of H 2 CO. Analysis of the spectral measurements indicates that a H 2 CO concentration of 150 parts in 10 9 by volume (ppbV) would produce a spe...

background: foundry workers are occupationally exposed to hazardous substances such as silica dusts and toxic gases. the aim of this study was to examine the effects of simultaneous exposure to complex mixtures of silica dust, formaldehyde, and triethylamine on lung function parameters. study design: a cross-sectional study. methods: this study was conducted on 55 male workers of core making un...

OBJECTIVE To investigate the relationship between several physiological variables that can be easily obtained during cycle ergometer gradual testing (for example, peak power output (W(peak)), Vo(2max), or ventilatory threshold (VT)) and actual (>50 km) time trials (TT) time performance during the Tour de France. METHODS We collected data in professional cyclists from the first TT of the 1998 ...

In this work, for the first time, a new and effective bulk modified carbon paste electrode (CPE) was prepared by TiO2 nanoparticles and chitosan and then Ni2+ ions were incorporated to this electrode by immersion of the modified electrode in nickel chloride solution. The values of electron transfer coefficient, charge-transfer rate constant and electrode surface coverage f...

In this work, for the first time, a new and effective bulk modified carbon paste electrode (CPE) was prepared by TiO2 nanoparticles and chitosan and then Ni2+ ions were incorporated to this electrode by immersion of the modified electrode in nickel chloride solution. The values of electron transfer coefficient, charge-transfer rate constant and electrode surface coverage f...

Formaldehyde has been classified as carcinogenic to humans (WHO IARC group 1). It causes leukaemia and nasopharyngeal cancer, and was described to regularly occur in alcoholic beverages. However, its risk associated with consumption of alcohol has not been systematically studied, so this study will provide the first risk assessment of formaldehyde for consumers of alcoholic beverages.Human diet...

BEIs: Threshold limit values for chemical substances and physical agents biological exposure indices. Cincinnati, OH: American Conference of Governmental Industrial Hygienists. *ACGIH. 1999b. Strontium chromate. 1999 TLVs and BEIs: Threshold limit values for chemical substances and physical agents biological exposure indices. Cincinnati, OH: American Conference of Governmental Industrial Hygien...