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In this study, two types of latex, Styrene–Butadiene Rubber (SBR) and Poly-Vinyl Acetate (PVA) were used as repair materials, and their various properties were examined. The assessments utilised Latex Modified Concrete (LMC) in ratios of 10%, 15%, and 20% to the weight of cement to investigate the properties of fresh and hardened concrete. The mechanical strength and durability of concrete were evaluated using porosity, water absorption, shrinkage, bonding behaviour, Coefficient of Thermal Expansion (CTE), and scaling resistance. The results indicated that LMC's mechanical properties improved, whereas its compressive strength decreased. The bonding strength between the LMC and the older concrete was more significant than between the Ordinary Portland Cement (OPC) and the substrate concrete. The SBR sample outperformed the PVA sample according to shrinkage and CTE results. Additionally, scaling resistance to deicing chemicals on concrete surfaces exposed to freezing-thawing cycles was satisfactory in concretes modified with both latexes. [ABSTRACT FROM AUTHOR]

Background: Recently, the use of posterior mucus flap has been introduced as a new technique for DCR, which has had a great success, as well as bone overlapping and minimal postoperative obstruction. Considering the need for these flaps to have a very good success, the purpose of this study was to examine the DCR endoscopic method using mucosal flaps for double-sided overlapping (as a new flap)., Methods: In this clinical trial study, 60 patients undergoing DCR endoscopy referring to Amin and Al-Zahra hospitals during 1396 to 1398 entered the study. Patients were divided into two groups, which included endoscopic DCR by using mucosal flaps for double-sided and non-flip overlapping. The success rate of surgery, postoperative pain and its complications were studied in two groups., Results: Among the complications observed after surgery, hematoma (6.7 in each group), bleeding (3.3% in each group) and nasal secretion (10% in the intervention group and 6.7% in the control group) were observed. No tear and obstruction of tear ducts were seen in the two groups. There was no significant difference between the two groups based on the complications of postoperative pain and the success rate of surgery (P>0.05)., Conclusion: Using the double-sided overlapping flap method, the results of the same operation were similar to using the non-flap method. Therefore, the use of both endoscopic DCR techniques with two-way overlapping flap and without using it were two effective methods with limited complications., Competing Interests: None., (AJCEI Copyright © 2020.)