• Structural Engineering and Mechanics
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• v.17 no.1
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• pp.99-112
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• 2004

It is known that lap splices in the longitudinal reinforcement of reinforced concrete (RC) bridge columns are not desirable for seismic performance, but it is sometimes unavoidable. Lap splices were practically located in the potential plastic hinge region of most bridge columns that were constructed before the 1992 seismic design provisions of the Korea Bridge Design Specification. The objective of this research is to evaluate the seismic performance of reinforced concrete (RC) bridge piers with lap splicing of longitudinal reinforcement in the plastic hinge region, to develop an enhancement scheme for their seismic capacity by retrofitting with glassfiber sheets, and to assess a damage of bridge columns subjected to seismic loadings for the development of rational seismic design provisions in low or moderate seismicity region. Nine (9) test specimens with an aspect ratio of 4 were made with three confinement ratios and three types of lap splice. Quasi-static tests were conducted in a displacement-controlled way under three different axial loads. A significant reduction of displacement ductility was observed for test columns with lap splices of longitudinal reinforcements, whose displacement ductility could be greatly improved by externally wrapping with glassfiber sheets in the plastic hinge region. A damage of the limited ductile specimen was assessed to be relatively small.

• Archives of Plastic Surgery
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• v.40 no.5
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• pp.517-521
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• 2013

Background Diabetes is characterized by chronic hyperglycemia, which can increase reactive oxygen species (ROS) production by the mitochondrial electron transport chain. The formation of ROS induces oxidative stress and activates oxidative damage-inducing genes in cells. No research has been published on oxidative damage-related extracellular superoxide dismutase (EC-SOD) protein levels in human diabetic skin. We investigated the expression of EC-SOD in diabetic skin compared with normal skin tissue in vivo. Methods The expression of EC-SOD protein was evaluated by western blotting in 6 diabetic skin tissue samples and 6 normal skin samples. Immunohistochemical staining was also carried out to confirm the EC-SOD expression level in the 6 diabetic skin tissue samples. Results The western blotting showed significantly lower EC-SOD protein expression in the diabetic skin tissue than in the normal tissue. Immunohistochemical examination of EC-SOD protein expression supported the western blotting analysis. Conclusions Diabetic skin tissues express a relatively small amount of EC-SOD protein and may not be protected against oxidative stress. We believe that EC-SOD is related to the altered metabolic state in diabetic skin, which elevates ROS production.

• Archives of Craniofacial Surgery
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• v.20 no.4
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• pp.246-250
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• 2019

Recently, there is a growing interest of hyperbaric oxygen therapy in many fields of medicine. We had a 43-year-old female patient presented with severe necrosis of the nose, philtrum, and upper lip due to retrograde arterial occlusion after nasolabial fold hyaluronic acid filler injection. Our patient went through 43 sessions of systemic hyperbaric oxygen therapy from December 2, 2017 to January 18, 2018. We administered 2.8 atmosphere absolute (ATA) for 135 minutes in the first session and the remaining sessions consisted of 2.0 ATA for 110 minutes. In reporting this case, we wish to provide a warning regarding the latent risk of filler injections and share our experience about minimizing soft tissue damage in the early stages with systemic hyperbaric oxygen therapy.

• Smart Structures and Systems
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• v.8 no.4
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• pp.385-398
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• 2011

This paper discusses the applicability of Acoustic Emission (AE) to assess the damage in reinforced concrete (RC) structures subjected to complex dynamic loadings such as those induced by earthquakes. The AE signals recorded during this type of event can be complicated due to the arbitrary and random nature of seismicity and the fact that the signals are highly contaminated by many spurious sources of noise. This paper demonstrates that by properly filtering the AE signals, a very good correlation can be found between AE and damage on the RC structure. The basic experimental data used for this research are the results of fourteen seismic simulations conducted with a shake table on an RC slab supported on four steel columns. The AE signals were recorded by several low-frequency piezoelectric sensors located on the bottom surface of the slab. The evolution of damage under increasing values of peak acceleration applied to the shake table was monitored in terms of AE and dissipated plastic strain energy. A strong correlation was found between the energy dissipated by the concrete through plastic deformations and the AE energy calculated after properly filtering the signals. For this reason, a procedure is proposed to analyze the AE measured in a RC structure during a seismic event so that it can be used for damage assessment.

• Journal of the Korea institute for structural maintenance and inspection
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• v.13 no.1 s.53
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• pp.115-124
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• 2009

In this study, a numerical analysis technique was newly developed to evaluate the damage propagation characteristics of concrete structures. To do this, numerical techniques are incorporated for the concrete members up to the compressive damage due to the bending compressive forces after the tensile crack based on the deformation mechanism. Especially, for the compressive damage stage after the tensile crack, the crack propagation process will be analyzed numerically using the concept of an equivalent plastic hinged length. Using this concept, it can be established that section forces, such as axial forces and the moment cracks takes place, can be related to the width of the crack making it possible to analyze the crack extension.

• Korean Journal of Agricultural Science
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• v.50 no.3
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• pp.539-547
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• 2023

This study evaluated the impact of rain shelters made of plastic film on spring frost damage and fruit quality in Asian pears ('Niitaka') over two years. In 2021, during the coldest spring days (between 0:00 am and 7:00 am), temperatures dropped to -1.20 - 0.43℃ at 120 cm and -1.33 - 0.57℃ at 200 cm above ground level in the control. Conversely, the rain shelter treatment maintained higher temperatures, -0.40 - 0.87℃ at 120 cm and -0.43 - 0.77℃ at 200 cm. Flower damage was significantly lower in the rain-sheltered group, with incidences of 1.3 and 6.9% at 120 and 200 cm, respectively, compared with 18.1 and 22.6% in the control group. Visual observations verified the prevention of frost adhesion on flower organs in the sheltered group, compared with noticeable pistil death and petal browning in the control group. In 2022, when temperatures remained above 0℃, fruitlet stalk length was 5 - 6 mm longer in the sheltered group. The cumulative impact of rain shelters was evident in the improved fruit quality over the two years. This study suggests resilient cultivation strategies in the face of climate change to reduce frost damage, increase productivity, improve fruit quality, and potentially increase incomes of the farmers.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.1D
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• pp.45-55
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• 2008

The objective of this research was to develop a VEPCD (ViscoElastoPlastic Continuum Damage) Model which is used to predict the behavior of asphalt concrete under various loading and temperature conditions. This paper presents the VEPCD model formulated in a tension mode and its validation using four hot mix asphalt (HMA) mixtures: dense-graded HMA, SBS, CR-TB, and Terpolymer. Modelling approaches consist of two components: the ViscoElastic Continuum Damage (VECD) mechanics and the ViscoPlastic (VP) theory. The VECD model was to describe the time-dependent behavior of HMA with growing damage. The irrecoverable (whether time-dependent or independent) strain has been described by the VP model. Based on the strain decomposition principle, these two models are integrated to form the VEPCD model. For validating the VEPCD model, two types of laboratory tests were performed: 1) a constant crosshead strain rate tension test, 2) a fatigue test with randomly selected load levels and frequencies.

• Archives of Plastic Surgery
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• v.32 no.4
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• pp.461-466
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• 2005

Despite the major advances in the microvascular surgery with success rates of up to 98%, failure and vascular complications still remain even in the experienced hands. Failure of blood to flow across an anastomosis is usually caused by three factors: (1) Technical errors; (2) Undetected damage more proximally or via vasospasm; or (3) A clot or a thrombus. The success of a microvascular surgery depends on the severity of the vascular injury and, proper debridement of an injured vessel, and the failure rate of microvascular anastomosis in cases of trauma is higher as the thrombogenic possibility is increased by the endothelial damage. From January to November in 2003, 460 patients were underwent microvascular surgery(270 replantations and 190 free flap transfers) and re-operations were performed in 15 cases. Cases were reviewed by clinical and operative records. In these cases, causes of post-operative circulation insufficiency were identified as 9 vascular spasms and 6 thromboses at the previous anastomotic site. The average of re-operative success rate was 73%(60% in replantations and 100% in free flaps). In conclusion, through precise postoperative monitoring and assessment, immediate surgical re-exploration could be performed when a vascular complication is suspicious, the success rate of microvascular surgery would be increased more.

• Archives of Plastic Surgery
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• v.35 no.6
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• pp.675-679
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• 2008

Purpose: In the orbital floor fracture, sensory impairment due to the damage of the infraorbital nerve is one of the most common symptom and complication. In this report, we have the assumption that tailoring of $medpor^{(R)}$ for decompression may have correlations to the damage and regeneration of the nerve. Methods: Among patients who had open reduction for pure orbital floor fracture in our hospital from March 2005 to March 2008, we selected 80 cases. In 40 cases, we inserted tailored $medpor^{(R)}$, and in other 40 cases, non-tailored $medpor^{(R)}$ was inserted. Patient's reports were obtained and analyzed, and the pin-prick test and the 2-point discrimination test on the infraorbital nerve regions were done for testing the sensory impairments. Results: The results show that the patients who adopted sculpture of $medpor^{(R)}$ showed higher tendency of recovery of sensory impairments in the patient's subjective report, static touch sensation, static two point discrimination using. And in postoperative 3 months, there are statistically significant recovery of sensory symptoms, signs and the result of sensory tests. Conclusion: From these results, tailored $medpor^{(R)}$ in reconstruction of orbital wall fracture may improve recovery of sensory impairments for decreasing of compression of infraorbital nerve.

• Archives of Plastic Surgery
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• v.36 no.1
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• pp.80-83
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• 2009

Purpose: Isolated hypoglossal nerve palsy is a rare manifestation of various underlying disease. This article presents a rare complication of general anesthesia associated with an surgical procedure on a case of zygomatic fracture. Methods: An 18-year-old female patient was referred to our department by painful swelling on her left zygomatic area after the traffic accident. Left zygomatic complex fracture was identified on the simple x-ray and facial bone CT scan, and the fracture was treated with open reduction and internal fixation under general anesthesia. On the first postoperative day, she complained of difficulty in swallowing solid food, dysarthria and deviated tongue to her right side. There was no abnormal findings on the neurological examination, brain MRI and routine chemistry. She was diagnosed with transient hypoglossal nerve palsy and dexamethasone with multi-vitamins was administrated intravenously for 5 days. Results: The symptoms were completely resolved by the ninth postoperative day and the patient was discharged without any other complications. Conclusion: The hypoglossal(cranial nerve XII)nerve supplies motor innervation to all of the ipsilateral extrinsic and intrinsic tongue muscles. The hypoglossal nerve damage may caused by the compression between the airway and the hyoid bone during the endotracheal intubation, and direct trauma due to excessive pressure or neck extension. We described a rare case of unintended injury to hypoglossal nerve and care must be taken not to cause the hypoglossal nerve damage especially in facial plastic surgery with excessive neck extension under general anesthesia.