: This study presents the effect of urea and sulfur admixture on compressive strength, chloride diffusion coefficient, and internal void distribution of concrete. Compressive strength of concretes with urea admixture by 5% increased by 5% relative to Control. However, that of concretes with urea admixture over 10% decreased. Chloride diffusion coefficient of concrete with urea and sulfur admixture decreased by 40% relative to Control. Additionally, the volume of internal void of concrete with urea and sulfur admixture decreased by 20% relative to Control. Therefore, it can be mentioned from test results that the use of adequate urea and sulfur admixture improves the mechanical properties and durability of concrete.

Introduction To our knowledge, there have been studies actively looking for patients with suspected SA in the Stroke Unit (SU), but most of them were conducted using a portable polysomnography (PSG), and no study has performed Level 1 PSG (L1PSG) to date. We conducted L1PSG to the acute stroke patients selected in the SU, and conducted L1PSG to patients who visited the Neurology Outpatient Clinic (NOC) with subjective SA symptoms at the same time. By comparison, we tried to find out the SA characteristics of acute stroke patients. Methods This study was conducted on patients admitted to SU from April 1, 2021 to October 31, 2022, and patients who visited NOC during the same period and underwent L1PSG. Among patients admitted to the SU, trained night shift nurses selected patients with SA symptoms with a modified mallampati score of 3 or higher. Cases under intracranial pressure control or other interventions were excluded. Outpatients were enrolled in patients who underwent L1PSG by visiting the NOC to examine only SA. The results of the pre-sleep questionnaire and L1PSG were compared. Results Of a total of 829 stroke patients admitted to SU, 31 SU patients received L1PSG, and during the same period, 74 patients received L1PSG for SA testing at NOC. The average age of SU and NOC was 56 and 57 years, and the median BMI was 26.9 and 26.4. In the survey, the ISI (7 vs 12, p=0.04) and PSQI (5 vs 7, p=0.021) scores were statistically significantly higher in NOC patients. As a result of the L1PSG, AHI (38.8 vs 23.1, p=0.027), AHI in Supine (59.3 vs 25.6, p=0.004) and NonREM AHI (36.3 vs 20.9, p=0.027) were statistically significantly higher in SU patients. Conclusion Patients screened SA at SU overlooked their symptom and thought their sleep quality was better than that of NOC patients, but the actual AHI was higher. In particular, acute stroke patients show a large difference in AHI in supine compared to NOC, so lateral position can be recommended when absolute bed rest is needed in situations where SA is suspected in SU. More follow-up studies will be needed. Support (if any)