1,721,132 research outputs found
Defining hormesis: The necessary tool to clarify experimentally the low dose-response relationship
No full textThe authors comment on Calabrese and Baldwin's paper 'Defining Hormesis', which, to date, is the first attempt to provide a definition of hormesis that goes beyond the different interpretations of this phenomenon reported in the literature. While appreciating the effort made in this study to place hormesis in a general and at the same time specific context, the authors believe some clarifications are needed as regards the quantitative features of this phenomenon. In this connection, they speculate on whether Calabrese and Baldwin think it appropriate to include hormesis assessment criteria in the document, referring in particular to those reported in a previous paper. The authors share Calabrese and Baldwin's conclusion that future experimental models designed to study hormetic phenomena must necessarily include the time factor, which not only guarantees this phenomenon will be detected, but is also able to detect the specific type of hormesis
Possibile ruolo, dell'ormesi nella valutazione del rischio in tossicologia occupazionale
No full textOver the past few decades there has been a gradual decline in concentrations of airborne chemical agents in the workplace. This improvement in the workplace has led to a concomitant need to study the effects of low dose exposure in order to assess possible risks. The paradigm used in toxicology to evaluate risk and to establish exposure limits for substances employed in industry, is that the dose-response relationship is expressed by a linear model for carcinogenic substances and by a threshold model for those which are not. Alongside these two traditional models, there has been a recent proposal to describe relationships using hormesis which is characterised by a biphasic curve corresponding to moderate stimulation resulting from response to low doses, and by inhibition at high doses. Although hormesis has been widely observed in experimental contexts, it still has to be tested in occupational toxicology to determine the possibility of obtaining a more accurate evaluation of the risk of exposure to low doses present in the workplace
Valutazione dell'esposizione professionale a tricloroetilene in un'azienda del settore tessile
No full textTrichloroethylene is used as a solvent and metal degreaser. It is potentially carcinogenic and produces mutagenic effects. The aim of this study was to determine personal exposure in a textile firm. Samplings and analyses were performed by means of active carbon absorption and gas chromatography with flame ionisation detection, respectively. Although findings revealed low exposure to trichloroethylene, it would be advisable to replace this substance in the work cycle
Environmental and biological monitoring of polycyclic aromatic hydrocarbons in an airport
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Assignment And Frequency Measurement Of Rotational Transitions Of 13cd3oh By Intracavity Laser Stark Spectroscopy
No full textWe present the results of an intracavity Stark spectroscopy experiment on the fundamental state of 13CD3OH. We use an optically pumped hybrid waveguide FIR laser, CH2F2 as active molecule, and 13CD3OH as absorbent molecule. No Brewster window is needed to separate the lasing gas from the absorbing deuterated methanol. An absorption line is assigned as E1 symmetry (n, K, J): (1,4,18) → (1,5,18) and its frequency is measured as 63.08631 cm-1 with a precision of a few parts in 107; two more absorptions are reported and a tentative assignment is given for one of them.374547551Moruzzi, G., Moraes, J.C.S., Strumia, F., (1992) Int. J. Infrared Millim. Waves, 13, pp. 1269-1312Pereira, D., Moraes, J.C.S., Telles, E.M., Scalabrin, A., Strumia, F., Moretti, A., Carelli, G., Massa, C.A., (1994) Int. J. Infrared Millim. Waves, 15, pp. 1-44Carli, B., Carlotti, M., Mencaraglia, F., Rossi, E., (1987) Appl. Opt., 26, pp. 3818-3822Inguscio, M., Ioli, N., Moretti, A., Strumia, F., D'Amato, F., (1984) Int. J. Infrared Millim. Waves, 5, pp. 1695-11639Moraes, J.C.S., Telles, E.M., Cruz, F.C., Scalabrin, A., Pereira, D., Carelli, G., Ioli, N., Strumia, F., (1992) Int. J. Infrared Millim. Waves, 13, pp. 1801-1823Inguscio, M., Moretti, A., Moruzzi, G., Strumia, F., (1981) Int. J. Infrared Millim. Waves, 2, pp. 943-986Inguscio, M., Moruzzi, G., Evenson, K.M., Jennings, D.A., (1986) J. Appl. Phys., 60, pp. R161-R192Xu, L.H., Lees, R.M., Mukhopadhyay, I., Johns, J.W.C., Moruzzi, G., (1993) J. Mol. Spectrosc., 157, pp. 447-466Moraes, J.C.S., Scalabrin, A., Pereira, D., Di Lonardo, G., Fusina, L., (1991) Infrared Phys., 31, pp. 365-372Moraes, J.C.S., Telles, E.M., Cruz, F.C., Scalabrin, A., Pereira, D., Carelli, G., Ioli, N., Strumia, F., (1991) Int. J. Infrared Millim. Waves, 12, pp. 1475-1486Telles, E.M., Moraes, J.C.S., Scalabrin, A., Pereira, D., Carelli, G., Massa, C.A., Moretti, A., Strumia, F., (1994) XIX Int. Conf. IRMMW (Sendai, Japan), pp. 524-525. , K. Sakai and T. Yoneyama edsInguscio, M., Minguzzi, P., Moretti, A., Strumia, F., Tonelli, M., (1979) Appl. Phys., 18, pp. 261-270Redon, M., Gastaud, C., Fourrier, M., (1979) IEEE J. Quantum Electron., QE-15, pp. 412-414Ioli, N., Moretti, A., Roselli, P., Strumia, F., (1986) J. Opt. Soc. Am. B, 3, pp. 867-869Inguscio, M., Ioli, N., Moretti, A., Strumia, F., D'Amato, F., (1986) Appl. Phys. B, 40, pp. 165-169Xu, L.H., (1992), PhD Thesis, University of New Brunswick, CAXu, L.H., private communicatio
Determinazione per mezzo della spettrometria di fluorescenza X dello zolfo totale particellare dell’aria.
No full textHormesis and industrial hygiene: A new hypothesis for low-dose response in occupational risk assessment
No full textThe study of Jayjock and Lewis, 'Implication of Hormesis for Industrial Hygiene', represents a challenge for the scientific community to consider hormesis as a possible working hypothesis for redefining risk assessment strategy for low-dose exposures in the realm of industrial hygiene. This invited commentary aims at examining some aspects of the study for which no proven and conclusive scientific evidence has yet been found, such as the limited nature of some statistical tests, the calculation of the safety factor, the place occupied by hormesis in industrial hygiene and, finally, the impact that scarce knowledge of this phenomenon and rejection by part of the scientific community has on the possibility, of using hormesis in the safeguarding of workers' health
Occupational exposure to low levels of organic and inorganic substances in a chemical plant for the production of terephtalic acid dimethyl ester
No full textThe aim of our study was the evaluation of personal exposure to chemical pollutants in workers employed in a plant for the production of terephtalic acid dimethyl ester. Chemical agents have been included in the monitoring program on the basis of the industrial process. In the plant, the oxidation of p-xylene is performed by air and the resulting acid is esterified with methyl alcohol. Purified terephtalic acid dimethyl ester is then utilized for the production of polyethylene terephtalate. The environmental monitoring included terephtalic acid dimethyl ester, p-toluic acid methyl ester, terephtalic acid, p-xylene, methylacetate, methylbenzoate, formic acid, acetic acid, methanol, and the catalysts cobalt acetate and manganese (II) acetate tetrahydrate. Personal exposure to the cited airborne substances was performed in the breathing zone of six workers. Air samplings were carried out by drawing air through glass fibre filters (terephtalic acid dimethyl ester, p-toluic acid methyl ester and terephtalic acid aerosols), by active adsorption (methanol, formic and acetic acids vapours). p-Xylene, methylacetate and methylbenzoate vapours were collected by passive sampling. Cellulose nitrate filters were used for cobalt and manganese salts samplings. Analyses were performed by UV detection high-performance liquid chromatography (terephtalic acid dimethyl ester, p-toluic acid methyl ester and terephtalic acid), flame ionization detection gas chromatography (p-xylene, acetic acid methyl ester and benzoic acid methyl ester), ion chromatography (formic and acetic acids) and inductively coupled plasma-mass spectrometry (cobalt and manganese). The results were evaluated according to the threshold limit values (TLVs) of the American Conference of Governmental Industrial Hygienists (ACGIH) and indicated that the environmental levels of the workplace pollutants were well below the threshold limit values-time weighed average (TLV-TWA) adopted by the American Conference of Governmental Industrial Hygienists for 2002, although for three substances the TLVs were not available
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