Upper airway muscle exercises outcome in patients with obstructive sleep apnea syndrome

AbstractBackgroundObstructive sleep apnea syndrome (OSAS) is an important disease that represent a challenge for both patients and physicians to reach optimum choice for treatment mostly because genesis of OSAS is multifactorial. Upper airway muscle function plays a major role in maintenance of the upper airway patency especially during sleep. Oropharyngeal exercises may be an effective treatment option for OSAS.ObjectiveAim of this study was to evaluate upper airway muscle exercise as method to treat OSAS.Patients and methods30 patients divided into 2 groups; Group I moderate OSAS and Group II: severe OSAS patients. Follow up, as regard ESS, AHI, oxygen saturation and snoring was done after 3months of oropharyngeal exercises.ResultsAfter end of study, daytime sleepiness and AHI improved significantly in group I (moderate OSA) 13 out of 15 patients shifted from moderate to mild OSAS. There was significant decrease in oxygen desaturation and snoring index. As for group II, there was decrease but not significant change in same parameters. Only for moderate OSAS, there was, significant decrease in neck circumference, which inversely correlated with changes in AHI (r=0.582; P<0.001).ConclusionUpper airways exercises can be a novel easy non invasive technique to improve AHI, O2 saturation and snoring thus used in treatment of OSAS patients mainly moderate type

Experimental and theoretical performance evaluation of parabolic trough mirror as solar thermal concentrator to thermoelectric generators

This paper presents the prospects of harnessing radiative heat from the sun with a parabolic trough mirror, as a solar thermal concentrator, in comparison to the mathematical model and experimental quartz-halogen concentrator model for the electrical energy conversion utilizing thermoelectric generators (TEG). The construction and design of TEG-setup along with Parabolic trough mirrors and quartz-halogen lamps are presented. The Parabolic trough mirror used as a focal point at a distance of 19.05 cm. With eight quartz-halogen concentrated heat, the maximum performance achieved at ΔT of 11.8 K, Voc of 292 mV and Isc of 95.8 mA, recorded at the concentrated hot-side surface temperature of 317.8 K. When compared to the natural solar concentrated heat, higher temperature of 473.15 K at the hot-side surface temperature of TG was achieved. It is concluded that the heat concentration of the parabolic mirror increases with an increase in the intensity of heat using natural solar radiations. The Voc of 1.76 V and Isc of 1.1 A at a temperature difference of 110 K were measured, which are in good agreement with validated mathematical results. The parabolic through mirror utilized is smaller in size and thus collected lesser sun rays than the larger dish style mirror, and hence the heat in the focal point was very low, for better results, parabolic trough mirror with higher surface area would be important for future experiments

Coal analysis using thermogravimetry

ABSTRACT Thermogravimetric analysis is being used increasingly today to obtain kinetic data related to coal decomposition. However, this method is open to criticism on the basis that the meaning of the activation energy of solid state reactions obtained from TG experiments is not clear. In this study a linear relationship between procedural activation energy and heat of reaction is developed. This is typical of elementary reactions of atoms and small radicals. The effects of alkali metal salts on the decomposition of coal under three gas atmospheres (N,. CO, and air) are investigated. Several features are reported such as the effect of the catalysts on coal conversion and CH,, CO and CO, emission. These are related to observed changes in activation energy

Knowing the ABCs: Teaching the principles of radiology to medical students in Turkey

Background: Radiology education in Turkey is mainly taught during clinical years of medical school and often lacks main principles. Exposure to the fundamentals of radiology at an early stage of medical education may drastically help students generate a better understanding of radiology and expand their interest in the specialty. With the Principles of Radiology Course that we provided, pre- and post-session tests, and assessment survey at the end of the course, we aimed to evaluate the effectiveness of such an online course among Turkish medical students. Methods: A total of nine online sessions on imaging modalities principles was developed by radiology professors. Each session was given through Zoom by radiologists from different U.S.-institutions to Turkish medical students from state (n = 33) and private (n = 8) universities. Pretests and post-tests were given to participants via Qualtrics before and after each session, respectively. Paired two-sample t-tests were conducted to detect the variance and p=-.05 was used as the significance level. An evaluation survey was distributed at the end of the course to collect their feedback through SurveyMonkey. Results: A total of 1,438 predominantly Turkish (99.32%) medical students engaged with this course. An average of 506 students completed both pre-test and post-test. There was a statistically significant (p <.001) increase in the scores in post-test (mean[range]:7.58[5.21–8.53]) relative to pre-test (mean[range]:5.10[3.52–8.53]). Four hundred and thirty-nine participants (F/M:63.33%/35.54%) completed the end-of-course survey. A total of 71% and 69.70% of the participants strongly agreed that the course would be useful in their clinical practice and had increased their understanding of radiology. They also reported that their level of confidence in the subjects had increased 68% and reached a weighted average of 3.09/4. The survey revealed that 396 (90.21%) of the participants strongly or somewhat agree that introductory principles and concepts should be presented in earlier years of medical education. Compared to in-person education, 358 (81.55%) found the course extremely or very convenient. Conclusion: Online lecture series consisting of the principles of the radiological imaging modalities can be offered to Turkish medical students to enhance their grasp of the various imaging modalities and their correct clinical application

Generation and Relaxation of Residual Stresses in Automotive Cylinder Blocks

There is direct proportionality between ultimate tensile stress (UTS) and residual stresses (RS). Residual stresses gradually decrease with decreasing cooling/quenching rates. Quenching in cold water develops highest, whereas air cooling produces lowest, residual stresses. Significant increase in RS is observed in specimens with low dendrite arm spacing (high solidification rate), while lower residual stresses are measured in specimens with high dendrite arm spacing (low solidification rate). For I-4 and V-6 engine blocks, there is refinement in microstructure due to the increase in solidification rate along the cylinder length. The developed residual stresses are normally tensile in both engine types. Air cooling following solution heat treatment produces higher RS compared to warm water and cold water quenching. Solution heat treatment and freezing lead to maximum RS relaxation where 50% of the stresses are reduced after the solution heat treatment step. Aging time and temperature are directly proportional to the residual stresses relaxation. Relaxation of RS also depends on the geometry and size of the workpiece. It should be mentioned here that the I-4 and V-6 cylinder blocks were provided by Nemak-Canada (Windsor-Ontario-Canada). Residual stress measurements technique and procedure are typical of those used by the automotive industry in order to provide reliable data for industrial applications supported by intensive experiments

The autonomous city: towards a critical geography of occupation

This paper explores the recent resurgence of occupation-based practices across the globe, from the seizure of public space to the assembling of improvised protest camps. It re-examines the relationship between the figure of occupation and the affirmation of an alternative ‘right to the city’. The paper develops a critical understanding of occupation as a political process that prefigures and materializes the social order which it seeks to enact. The paper highlights the constituent role of occupation as an autonomous form of urban dwelling, as a radical politics of infrastructure and as a set of relations that produce common spaces for political action

Effect of calcium chloride and calcium acetate on the reactivity of a lignite coal at low heating rate

The effect of calcium chloride and calcium acetate on the rate of decomposition of a lignite coal and its char was investigated under both pyrolysis and combustion conditions. The experiments were undertaken in a thermogravimetric analyzer under low (20°C min-1) and intermediate (2100°C min-1) heating rates. Both calcium chloride and calcium acetate slightly reduced the amount of coal decomposed at 105 N m-2 in a nitrogen atmosphere. However, the inhibiting effect of calcium acetate was dependent on the sample size and packing density. In the presence of oxygen, addition of calcium chloride to coal produced two opposite effects: at low temperatures an inhibiting effect due to the chloride and at higher temperatures a promoting effect due to the catalytic role of the calcium. Lastly, the additives reduced the apparent activation energy and increased the heat reaction of the lignite coal. © 1988