The aim of this review is to provide a general overview of the relationship between occupational stress and gastrointestinal alterations. The International Labour Organization suggests occupational health includes psychological aspects to achieve mental well-being. However, the definition of health risks for an occupation includes biological, chemical, physical and ergonomic factors but does not address psychological stress or other affective disorders. Nevertheless, multiple investigations have studied occupational stress and its physiological consequences, focusing on specific risk groups and occupations considered stressful. Among the physiological effects of stress, gastrointestinal tract (GIT) alterations are highly prevalent. The relationship between occupational stress and GIT diseases is evident in everyday clinical practice; however, the usual strategy is to attack the effects but not the root of the problem. That is, in clinics, occupational stress is recognized as a source of GIT problems, but employers do not ascribe it enough importance as a risk factor, in general, and for gastrointestinal health, in particular. The identification, stratification, measurement and evaluation of stress and its associated corrective strategies, particularly for occupational stress, are important topics to address in the near future to establish the basis for considering stress as an important risk factor in occupational health.© 2013 Baishideng Publishing Group Co., Limited. All rights reserved.Key words: Stress; Occupation; Gastric alterations; Gastrointestinal tract diseases; Health risks Core tip: In workers, the combination of personality patterns (anxiety/depression), stress and negative emotions contribute to gastrointestinal tract (GIT) alterations. In particular, jobs that produce privation, fatigue, chronic mental anxiety and a long past history of tension, frustration, resentment, psychological disturbance or emotional conflict have been shown to produce gastric ulcers. Irritable bowel syndrome and functional dyspepsia also have significant co-morbidity with mood alterations. Workers with unipolar depression have been shown to be more prone to present irritable bowel syndrome-like symptoms. Moreover, three systems are known to participate in the GIT alterations of workers: sympathetic autonomic nervous system, the hypothalamic-pituitary-adrenal axis and genetic factors.Huerta-Franco MR, Vargas-Luna M, Tienda P, DelgadilloHoltfort I, Balleza-Ordaz M, Flores-Hernandez C. Effects of occupational stress on the gastrointestinal tract. World J Gastrointest Pathophysiol 2013; 4(4): 108-118 Available from: URL:

The time evolution of the inhomogeneous curing process of polystyrene emulsions is studied using a variant of the conventional photoacoustic (PA) technique. The thermal effusivity, as a function of time, is determined in order to monitor the sintering process of a styrene emulsion in different steps of the manufacturing procedure. PA measurements of thermal effusivity show a sigmoidal growth as a function of time during the curing process. The parameterization of these curves permits the determination of the characteristic curing time and velocity of the process. A decreasing of the curing time and an increasing curing velocity for the final steps of the manufacturing process are observed. The feasibility of our approach and its potentiality for the characterization of other curing process are discussed.

The dynamics of blood and hemolymph sedimentation is studied in real time using the photoacoustic technique. A modified configuration of a conventional photoacoustic cell is used, where the advantage of this methodology is that the sample is not illuminated directly and that the process can be monitored through the measurement of the thermal contact between a reference material and the blood. It is demonstrated that during the process the thermal effusivity decreases at the region of contact between the sample and the reference materials. The usefulness of these results in real time monitoring using photothermal techniques is discussed.

No abstract

The impedance spectroscopy technique (IST) was used for studying the effect of a 0.5 T magnetic field on the electrical properties of whole human blood. A Solartron SI 1260 spectrometer was used to measure the impedance spectra of magnetic field exposed blood samples compared to non-exposed samples. An equivalent electrical circuit model, consisting in a resistance Rs in series with a parallel circuit formed by a constant phase element (CPE) and another resistance Rp, is proposed to fit the data in both cases. The experiment used 3 ml human blood samples from 160 healthy donors. A Wilcoxon matched pairs statistical test was applied to the data. The data analysis seems to show a statistically significant increase of the values of resistance Rp (Z = 5.06, P < 0.001) and capacitance CT (Z = 3.32, P < 0.001) of the blood exposed to magnetic field, by approximately 10.4% and 1.9%, respectively.