Smoking status in relation to obstructive sleep apnea severity (OSA) and cardiovascular comorbidity in patients with newly diagnosed OSA

Introduction: the relationship between smoking and sleep disturbance has been well documented. Smoking is a common risk factor for both obstructive sleep apnea (OSA) and cardiovascular diseases. The study aimed to: 1) evaluate the incidence of newly diagnosed OSA in patients presenting with symptoms suggestive of a sleep disorder, 2) assess the relation between smoking status and OSA severity; and 3) compare the prevalence of cardiovascular comorbidities in ever- and never smokers with newly diagnosed OSA. Material and methods: a retrospective analysis of 5,353 patients suspected of OSA was performed. OSA was diagnosed on the basis of polysomnography. The influence of smoking status on indices of OSA severity was evaluated and the incidence of self–reported cardiovascular diseases and diabetes mellitus type 2 was analyzed in relation to smoking history. Results: OSA was diagnosed in 3,613 patients (67.5%); of these, 21.6% were ever-smokers. Smokers with OSA had a higher apnea-hypopnea index [AHI; 31 (18.4–53.29) vs 29 (18.3–47.7), p = 0.03], lower mean oxygenation during sleep [92 (90–93) vs 92 (91–94), p < 0.01] and a higher daytime sleepiness (Epworth Sleepiness Scale score 11.7 ± 5.5 vs 11.0 ± 5.5, p < 0.001). The most frequent comorbidity was hypertension, followed by obesity, diabetes mellitus type 2 and coronary artery disease, with a statistically higher incidence of hypertension in non-smokers (59.2 vs 64.7 %, p = 0.005). Conclusion: smoking is related with OSA severity and increased daytime sleepiness. Our study confirmed the elevated frequency of cardiovascular comorbidities in OSA patients in general but did not show an increased incidence of these comorbidities in smokers

TIME MANAGEMENT – ON EXAMPLE OF MODEL DEPARTMENT OF HEAT TREATMENT OF AlSiMg ALLOY

A review of various models of the management and techniques using in the production sector to create a proposal of an example in a model department of the heat treatment of AlSiMg alloys. The results of these works were a cost reduction in the final product to help the customer by creating benefits for them – for example, in lowering prices. If we could use the proposed models of management and optimization of technology to implement a unique model in the department of heat treatment, we can increase the mechanical properties of casting due to the economic benefits. To create a unique model of management in the department of heat treatment, it is necessary to have two ways of knowledge about the economy and foundry know-how of innovation technology – that was improved in this article

Editors’ Note on the Special Section, Journal of Telecommunications and Information Technology, 2021, nr 2

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TECHNOLOGY OF MANUFACTURING FOUNDRY CORES USING ADDITIVE METHODS

The use of additive manufacturing methods for the production of sand cores with organic binders is currently the latest trend in small and unit production, as it allows for a quick and simple way to get a final cast part; this is known as Rapid Prototyping. In this article, manufactured additive method cores were analyzed that were made of quartz sand with furfuryl resin and cores made of synthetic sand. Derivatographic measurements were compared, and examples of the high complexity cores are shown. Furthermore, the aspect ratio of the grains was determined by microscopic observation. Each type of core was characterized by a different flexural strength and differentiated results of abrasion. The results were collected and compared

Single Hysteresis Model for Limited-availability Group with BPP Traffic, Journal of Telecommunications and Information Technology, 2013, nr 3

This paper presents a single hysteresis model for limited-availability group that are offered Erlang, Engset and Pascal traffic streams. The occupancy distribution in the system is approximated by a weighted sum of occupancy distributions in multi-threshold systems. Distribution weights are obtained on the basis of a specially constructed Markovian switching process. The results of the calculations of radio interfaces in which the single hysteresis mechanism has been implemented are compared with the results of the simulation experiments. The study demonstrates high accuracy of the proposed model

EVALUATION OF CHANGES OF STEREOLOGICAL PARAMETERS OF EUTECTIC PHASES IN AlSiMg ALLOY AFTER PRECIPITATION HARDENING

Qualitative microstructure investigations of the AlSiMg alloy’s microstructure in both its original state (with the characteristic primary structure) and after precipitation hardening revealed the significant heterogeneity of the eutectic phases concerning their shape, size, and distribution. An evaluation of the stereological parameters of the eutectic phases was carried out. The computer-image analysis was performed in order to define the fraction of the relative volume and shape of the eutectic phases and to establish their influence on the mechanical properties