• Advances in nano research
• /
• v.13 no.1
• /
• pp.87-96
• /
• 2022

Drug self-delivery systems can easily realize combination drug therapy and avoid carrier-induced toxicity and immunogenicity because they do not need non-therapeutic carrier materials. So, designing appropriate drug self-delivery systems for specific diseases can settle most of the problems existing in traditional drug delivery systems. Retinal pigment epithelium is very important for the homeostasis of retina. However, it is vulnerable to oxidative damage and difficult to repair. Worse still, the antioxidants can hardly reach the retina by non-invasive administration routes due to the ocular barriers. Herein, the targeted group (folic acid) and antioxidant (melatonin) have been grafted on the surface of ZnO quantum dots to fabricate a new kind of drug self-delivery systems as a protectant via eyedrops. In this study, the negative nanoparticles with size ranging in 4~6 nm were successfully synthesized. They could easily and precisely deliver drugs to retinal pigment epithelium via eyedrops. And they realized acid degradation to controlled release of melatonin and zinc in retinal pigment epithelium cells. Consequently, the structure of retinal pigment epithelium cells were stabilized according to the expression of ZO-1 and β-catenin. Moreover, the antioxidant capacity of retinal pigment epithelium were enhanced both in health mice and photic injury mice. Therefore, such new drug self-delivery systems have great potential both in prevention and treatment of oxidative damage induced retinal diseases.

• Journal of the Korea Institute of Building Construction
• /
• v.21 no.6
• /
• pp.529-538
• /
• 2021

In this study, the compressive strength and water contact angle were measured before and after surface abrasion of mortar specimens prepared by mixing two types of water repellents and two types of sands. In addition, the hydration products and chemical bonding of cement mortar by repellent were examined using X-ray diffraction(XRD), thermogravimetry-differential thermal analysis(TG-DTA), and Fourier-transform infrared spectroscopy(FT-IR) to evaluate the performance of these cement mortar mixtures as repair materials. We found that the compressive strength of the cement mortar with water repellent added was decreased compared to that of the plain cement mortar, and that of the oligomeric system was higher than that of the monomeric system. We further found that the contact angle of mortar with water repellent added was increased compared to that of the plain cement mortar, and that of the oligomeric system was increased compared to that of the monomer.

• Journal of Korean Foot and Ankle Society
• /
• v.26 no.4
• /
• pp.171-176
• /
• 2022

Purpose: This study reports on a series of patients with chronic lateral ankle instability that underwent the Brostrom procedure with suture tape augmentation and allowed early unrestricted weight-bearing in a simple stirrup brace. Materials and Methods: This retrospective study was conducted on 36 patients (22 males and 14 females of mean age 34 years [range 23~48 years]) with chronic lateral ankle instability treated using the Brostrom procedure using suture tape augmentation and inferior extensor retinaculum reinforcement with a fiber-wire connected to a SwiveLock screw inserted into the talus. When possible, patients started unrestricted weight-bearing in a stirrup brace from the third postoperative day. Demographics and functional outcomes, including American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot, visual analogue scale (VAS), and satisfaction scores, were recorded. In addition, varus stress radiographs obtained before and 24 months after surgery were compared. Patients were followed for a mean 29 months (range 25~40 months). Results: Mean AOFAS ankle-hindfoot scores increased from 51 points preoperatively to 92 points at final follow-up, and mean VAS decreased from 6.8 to 1.2 points. Mean patient satisfaction scores were 8.7 at 12 months and 9.6 at 24 months. Stress radiographs demonstrated that talar tilt decreased from a mean 18 degrees preoperatively to 7 degrees at 24 months. Conclusion: Early unrestricted weight-bearing in a stirrup brace following the Brostrom procedure with suture tape augmentation is a successful protocol for treating chronic lateral ankle instability.

• Journal of dental hygiene science
• /
• v.22 no.1
• /
• pp.9-19
• /
• 2022

Background: The purpose of this study was to identify the differences in the importance of oral pathology learning objectives for instructors and clinical dental hygienists and provide basic data that can guide learning objectives for acquiring practically necessary basic knowledge in the clinical field. Methods: Through the first-stage expert meeting, 27 items with less than four points out of 129 learning objectives in 15 detailed areas were deleted, 12 additional opinions were reflected, 114 learning objectives were set, and a survey was conducted with 253 people. Results: There were statistically significant differences in 92 items after examining the difference between professors and clinical dental hygienists. Among the areas of inflammation and repair, "Can explain the five symptoms of inflammation" had the highest with a score at 4.76 in the case of the professors. Among the areas of tooth damage, "Can explain abrasion" had the highest with a score at 4.61 in the case of the clinical dental hygienists. Conclusion: I would like to propose the existing 15 detail areas and 129 learning objectives as 14 detail areas and 98 learning objectives and strengthen the job competency of dental hygienists in the future. First, you need to develop competencies that are highly relevant to your work. Second, it is necessary to develop related textbooks and educational materials based on revised learning objectives and competencies. Third, based on revised learning objectives, the dental hygienist national examination should be improved. Through these changes in education, the education of oral and maxillofacial disease subjects should strengthen job competencies among dental hygienists with learning objectives that can be applied to actual clinical practice based on basic knowledge rather than knowledge orientation. In addition, it is possible to improve the quality of dental hygiene studies.

• Medical Lasers
• /
• v.8 no.2
• /
• pp.50-58
• /
• 2019

Background and Objectives Low-level light therapy (LLLT) is an application of low-power light for various purposes such as promoting tissue repair, reducing inflammation, causing analgesia, etc. A previous study suggested the effect of light emitting diode (LED) light with the wavelength of 740 nm for promoting wound healing of corneal epithelial cells. This current study aimed to confirm the effect of LLLT for managing inflammation of a dry eye disease (DED) mouse model. Materials and Methods A total of 50C57BL/6 female mice were randomly grouped into 5 groups to compare the effect of LLLT:1) Control group, 2) Only LLLT group, 3) Dry eye group, 4) LLLT in dry eye group, and 5) Early treatment group. DED was induced with 4 daily injections of scopolamine hydrobromide and desiccation stress for 17 days, and LLLT at 740 nm was conducted once every 3 days. To analyze the effect of LLLT on the DED mouse model, tear volume, corneal surface irregularities, and fluorescence in stained cores were measured, and the level of inflammation was assessed with immunohistochemistry. Results The DED mouse model showed significant deterioration in the overall eye condition. After LLLT, the amount of tear volume was increased, and corneal surface irregularities were restored. Also, the number of neutrophils and the level of inflammatory cytokines significantly decreased as well. Conclusion This study showed that LLLT at 740 nm was effective in controlling the corneal conditions and the degree of inflammation in DED. Such findings may suggest therapeutic effects of LLLT at 740 nm on DED.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.29 no.5A
• /
• pp.503-510
• /
• 2009

Latex modified concrete (LMC) is a successful polymer-portland cement concretes, which have been developed and used for many years, in overlaying bridge decks and resurfacing industrial floors. The excellent bond strength to substrate, easy application and high resistance to impact, abrasion, wear, aggressive chemicals and freeze-thaw deterioration have made this material used widely. The objective of this study was to determine experimentally the load-deflection response and ultimate strength of reinforced RC beams. The cracking patterns and the mode of failure were observed. Because of excellent bond strength and repairing effects, the RC beams repaired by LMC at compression or tension zone showed over 100% recovery from damaged structures. The RC beams overlaid by LMC showed significant improvement at load carrying capacity as overlay thickness increases. However, the beams repaired of tension zone without shear stirrups almost showed no strengthen effect, and indicated an interfacial failures. The interfacial behavior was estimated by numerical method adopting the concept of shear flow.

• Journal of Korean Foot and Ankle Society
• /
• v.27 no.1
• /
• pp.12-16
• /
• 2023

Purpose: Postoperative exercise for acute Achilles tendon rupture is important for a patient's return to daily life and sports. On the other hand, the protocol requires considerable effort to educate patients and continuous checking. This study evaluated the outcome of a new simple and delayed rehabilitation protocol after Achilles tendon rupture repair. Materials and Methods: From July 2014 to November 2020, one hundred eighty-three patients were operated on by one surgeon. The exercise protocol was classified into two methods. One group (immediate protocol, control group) started immediate full weight bearing with a 20° plantar flexion range of motion from two days postoperatively. Ankle dorsiflexion was restricted to 0°. The other group (delayed protocol, case group) started full weight bearing with a controlled ankle motion boot from two weeks postoperatively. No range of motion exercise was allowed until six weeks postoperatively. Age, sex, body mass index, ankle range of motion, muscle power, time to return to previous physical activity, functional score, and complication rate were evaluated. The results of the two groups were compared using a Mann-Whitney test. Statistical significance was set as p<0.05. Results: The range of motion, double heel rising, and one-leg standing were achieved faster in the control group (p<0.05). However, single-heel rising, repeated single-heel rising, return to previous activity (work, run, and sport), and functional scores showed no statistical difference (p>0.05). Conclusion: Simple and delayed postoperative rehabilitation of acute Achilles tendon rupture without active range of motion exercises showed satisfactory functional results and a low complication rate.

• Steel and Composite Structures
• /
• v.45 no.1
• /
• pp.83-100
• /
• 2022

Timber is one of the few natural, renewable building materials and glulam is a type of engineering wood product. In the present work, timber-based braces are applied for retrofitting midrise Special Moment Resisting Frame (SMRF) using two types of timber base braces (Timber base glulam, and hybrid Timber-Steel-BRB) as alternatives for retrofitting by traditional steel bracings. The improving effects of adding the bracings to the SMRF on seismic characteristics of the frame are evaluated using load-bearing capacity, energy dissipation, and story drifts of the frame. For evaluating the retrofitting effects on the seismic performance of SMRF, a five-story SMRF is considered unretofitted and retrofitted with steel-hollow structural section (HSS) brace, Glued Laminated Timber (Glulam) brace, and hybrid Timber-Steel BRB. Using OpenSees structural analyzer, the performance are investigated under pushover, cyclic, and incremental loading. Results showed that steel-HSS, timber base Glulam, and hybrid timber-steel BRB braces have more significant roles in energy dissipation, increasing stiffness, changing capacity curves, reducing inter-story drifts, and reducing the weight of the frames, compared by steel bracing. Results showed that Hybrid BRB counteract the negative post-yield stiffness, so their use is more beneficial on buildings where P-Delta effects are more critical. It is found that the repair costs of the buildings with hybrid BRB will be less due to lower residual drifts. As a result, timber steel-BRB has the best energy dissipation and seismic performance due to symmetrical and stable hysteresis curves of buckling restrained braces that can experience the same capacities in tension and compression.

• Journal of Korean Foot and Ankle Society
• /
• v.28 no.1
• /
• pp.15-20
• /
• 2024

Purpose: Achilles tendon rupture is a frequently encountered ankle pathology associated with a substantial burden of intense pain and functional deficits. Chronic Achilles tendon ruptures with considerable defects pose intricate repair challenges that are often marred by complications such as re-rupture and persistent pain. Various treatment methods, including allograft transplantation, have been proposed, but the literature on this technique is limited. In this study, we propose a surgical approach utilizing allotendon transplantation and a calcaneal tunneling technique and provide clinical evaluation details. Materials and Methods: Fifteen patients with chronic Achilles tendon ruptures treated with allotendon between 2020 and 2022 were included in the study. Patients were evaluated at 1, 3, and 6 months postoperatively using Visual Analog Scale (VAS) scores and Achilles Tendon Total Rupture Scores (ATRSs). Complications were assessed postoperatively. Results: The average VAS score was 7 before surgery, 7.3 immediately after surgery, and 4.3 at 1 month, 2.5 at 3 months, and 1.3 at 6 months after surgery. Because the sample was limited to 15 individuals and distributions were non-normal, the analysis was conducted using the non-parametric Wilcoxon's signed-rank test, and statistical significance was accepted for p-values<0.05. Results showed a significant improvement in ATRS and VAS scores versus preoperative and immediate postoperative values. VAS scores showed a decreasing trend after surgery, whereas average ATRS scores increased from 14 before surgery, 33.8 at 1 month, 82.7 at 3 months, and 93.9 at 6 months. Conclusion: This study suggests that allograft transplantation using the described calcaneal tunnel technique provides an effective treatment for chronic Achilles tendon ruptures. However, extensive research and long-term clinical trials are required to validate and better understand the technique's efficacy.

• Structural Engineering and Mechanics
• /
• v.90 no.5
• /
• pp.467-480
• /
• 2024

The mechanical properties and durability of concrete pavements may be degraded in extreme situations, resulting in the need for partial repair or total replacement. During the past few decades, there has been a growing body of research on substituting a portion of Portland cement with alternative cementitious materials for improving concrete properties. In this study, two different configurations of powdered and granulated blast furnace slag were implemented, replacing fine aggregates (by 12 wt.%) and Portland cement (by 0, 20, 40, and 60 wt.%) in the making of roller-compacted concrete (RCC) mixes. The specimens were fabricated to investigate the mechanical properties and durability specifications, involving freeze-thaw, salt-scaling, and water absorption resistance. The experimental results indicated that the optimum mechanical properties of RCC mixes could be achieved when 20-40 wt.% of powdered slag was added to concrete mixes containing slag aggregates. Accordingly, the increases in compressive, tensile, and flexural strengths were 45, 50, and 28%, in comparison to the control specimen at the age of 90 days. Also, incorporating 60 wt.% of powdered slag gave rise to the optimum mix plan in terms of freeze-thaw resistance such that a negligible strength degradation was experienced after 300 cycles. In addition, the optimal moisture content of the proposed RCC mixtures was measured to be in the range of 5 to 6.56%. Furthermore, the partial addition of granulated slag was found to be more advantageous than using entirely natural sand in the improvement of the mechanical and durability characteristics of all mixture plans.