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The equivalence of quasi-chemical and statistical description of adsorbate molecule association in a localised adsorption monolayer on a homogeneous solid surface

Abstract

The analysis of Berezin and Kiselev’s concept assuming linear association of molecules in a localised adsorption monolayer on the homogeneous surface of a solid adsorbent was carried out. An inconsistency due to the lack of consideration of equilibrium concentration of free adsorption sites in the formulation of the expression for the association constant has been pointed out. It was shown that the correct form of this function leads to the final adsorption equation being identical to the specific case of the Fowler-Guggenheim equation. The obtained result has been generalised to cases of branched adsorbateadsorbate associations. A new adsorption equation limiting the association to at most the dimers has been introduced. Critical conditions for the two-dimensional condensation of the adsorption layer were determined. By applying the formalism of canonical ensemble, full equivalence of the phenomenological and statistical methods was demonstrated in the description of the intermolecular interactions in the localised adsorption monolayer.

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Extrinsic allergic alveolitis induced by spores of Penicillium in a salami factory worker

Abstract

We report a case of subacute extrinsic allergic alveolitis due to occupational exposure to Penicillium spores in a 43-years old female working in a salami factory that developed a dry cough that gradually evolved to productive cough, shortness of breath, fatigue and body weight loss. Over time she complained of several episodes of flu-like symptoms that worsen around the periods in which she removed the excess mould from the surface of the salami a work. On admission, physical examination revealed crackles in both lungs on chest auscultation, pulmonary function tests showed a restrictive pattern with reduced diffusion capacity of carbon monoxide and imagistic tests identified centrilobular nodules of ground-glass opacity in both lung fields, particularly in the upper lobes. BAL showed lymphocytosis associated with neutrophilia, a pattern consistent with EAA. She was put on systemic corticosteroids and ceased exposure. The patient was compliant and after one year her medication was gradually withdrawn and in the absence of exposure, symptoms and pulmonary function normalized. The reported case had a favorable outcome due to relatively early detection and absence of exposure. Currently, the identification and removal of the causative agent remains the cornerstone of prevention, evolution and prognosis.

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Obstructive sleep apnea: from the beginnings, to the risk factors and to occupational medicine assessment

Abstract

Over the last thirty years, the pathogenesis of obstructive sleep apnea syndrome (OSAS) has begun to be elucidated worldwide due to the presence of standardized diagnostic and treatment. In adults, the clinical diagnosis may be suggestive of OSAS when symptoms like fatigue, lack of concentration, poor work performance, absenteeism, daytime sleepiness, insomnia, snoring, nocturnal respiratory distress or apnea episodes witnessed by others are present. Some medical conditions found in employees’ personal history such as craniofacial abnormalities, some endocrine diseases, arterial hypertension, especially resistant arterial hypertension, coronary artery disease, atrial fibrillation, congestive heart failure, stroke, obesity, diabetes mellitus, cognitive dysfunction or mental disorders may be the alarm signal for OSAS. The assessment of all risk factors, clinical presentation and diagnosis must become an important part of occupational medical examinations and performed in all workers due to its major public health potential and impact on survival. The early identification of OSAS among workers performed by the occupational physician can potentially reduce the risk of work injuries and fatalities. In conclusion, OSAS is a complex entity and an important public health problem. The delay in diagnosis and treatment contributes to the increase of healthcare services demand and implicitly to general mortality.

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The practical aspects of implementation of the thrust allocation procedure for a multi-propulsor underwater robot

Abstract

This article addresses the practical aspects of the synthesis of an automatic control system for the thrust allocation strategy in the propulsion system of an unmanned underwater vehicle. The vehicle under consideration is a robot submarine equipped with a multi-propulsion system providing four degrees of freedom of movement. The power distribution algorithms are based on limited optimisation methods that allow the determination, on the basis of generalised torques and forces, of how much thrust is required to be produced by individual propulsors. Considering the issue of power distribution as a task of square and linear programming, two algorithms of thrust allocation were proposed and compared. The conducted model tests made it possible to evaluate their quality and efficiency in relation to speed and computational complexity.

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Scientific diving in natural sciences

Abstract

Scientific diving is increasingly being used for numerous studies. Moreover, this form of diving allows for the conduction of interdisciplinary research. The current nomenclature of this type of dive is defined as scuba diving to collect information to support science by using diving techniques. Underwater research is particularly important in the natural sciences where it allows for the non-invasive observations of fauna and flora of aquatic ecosystems in their natural environment. At the same time, the use of diving for scientific purposes avoids mistakes made in random sampling, which is related to the use of classical sampling methods. As a result, such diving is crucial in systematic, ecological and behavioural analysis. Nevertheless, dive techniques, however versatile, require optimisation, separate study and systematisation, depending on the type of research conducted. This article is an attempt to present an outline of the topic, to systematise basic concepts in presenting the principles of legal regulations in Poland and abroad..

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Securing the hyperbaric treatment of decompression sickness in the polish navy

Abstract

Recently, the Polish Navy has extended its capability for the implementation of underwater works with autonomous dives conducted beyond the saturation zone to a depth of 80 mH2O. In the near future it is also planned to introduce long-term dives within typical depths of the saturation plateau.

One of the activities resulting from the analysis of the risk associated with the extension of these competences is the need to conduct a critical review of the system for securing hyperbaric treatment of cases of decompression sickness1.

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Sick building syndrome, a crossroad in modern occupational medicine assessment

Abstract

Sick building syndrome (SBS) is a complex syndrome consisting of non-specific symptoms with an onset associated with subjects’ presence in some modern building and the disappearance of symptoms shortly after they leave it. The effects of SBS may be the result of a series of protective reactions of the human body triggered by various types of surrounding environment, further suggesting that the human response could be based on a three-phase biological model: sensory perception, low degree inflammatory reactions and environmental stress reactions. Besides stress created by the discomfort of people who develop symptoms, SBS is the cause of an extensive loss of productivity, sickness absenteeism, wasted time in complaints with all the legal punitive issues that arise from them. The subjects diagnosed with SBS are hard to follow-up over time due to workers often leaving their jobs and being lost from cohort databases. Achieving a reputation of a “sick building” may prove difficult to rehabilitate even after expensive repairs and upgrades. In extreme cases closure and even demolition can occur. SBS is an evolving concept and this review we will present part of this evolution and what are the major challenges for its definition.

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Stress vulnerability assessment among medical and political science and public administration students

Abstract

Context. Stress is a complex psychosocial phenomenon that significantly influences health. The individual differences in stress response depend on sensitivity to stressors, named “stress vulnerability”.

Objectives. The aims of the study were to determine the level of perceived vulnerability to stress and compare stress vulnerability among students from 2 universities in Bucharest: University of Medicine “Carol Davila” and National University of Political Studies and Public Administration.

Methods. An approximately equal number of students from the two selected universities completed the Romanian version of the Miller-Smith stress vulnerability questionnaire.

Results. A number of 86 (60 women and 26 men) students agreed to participate. Average age was 23.56 years with a standard deviation of 4.86 years. The high vulnerability group included 18 (38%) medical students and 27 (60%) political science and public administration students. The difference was statistically significant (chi2 test, p=0.02) between the two groups. The average health score for medical students (MS) was 15.97, with a median of 15, while for the political science and administration students (PSPAS) the average health score was 24.91, with a median of 26. The average psychosocial score for MS group was 20.41 and the median was 20. In the PSAPS group, the psychosocial score was 26.14 and the median 24. The difference was statistically significant for both health score (p<0.00001) and psychosocial score (p=0.0006).

Conclusions: Stress is a common problem among undergraduated students. In this study the vulnerability to stress was higher for students PSAPS group compared to the students from MS group.

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Teaching communication for safety in selected water based recreational disciplines

Abstract

This paper describes the concept of didactic communication and verifies the course of teaching selected disciplines of water based recreation, i.e. swimming (at the standard technique level), handling a sailing boat whilst undertaking simple manoeuvres, and the basics of diving. At the same time, research in the area of experiments conducted in the field of teaching methods of these disciplines was reviewed in terms of teaching effectiveness, as well as the health and safety of the participants, and ways of communicating while in, on and under the water. Communication between an instructor and a student in any environment which is different from the norm, is difficult owing to its specificity. Additionally, teaching skills on, in or under water requires strict observance of safety rules. Lack of student’s readiness to act in a different water environment, be that based on anxiety or fear, may interfere with or, even prevent didactic communication. Consequently, the effectiveness of teaching decreases. The aim of this work is to search for innovative forms of information transfer that will enable a permanent change in the student’s behaviour, especially when acting in a difficult environment – on the water, in the water and under the water. There are premises to believe that immediate verbal instruction and emphasising the metalinguistic function in it should improve the quality and effectiveness of the process of teaching activities in various water based environments.

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