• The Korean Journal of Pain
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• v.30 no.4
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• pp.281-286
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• 2017

Background: Magnetic resonance imaging (MRI) of the spine is the preferred diagnostic tool for pathologic conditions affecting the spine. However, in patients receiving epidural corticosteroid injection (ESI) for treatment of spinal diseases, there is a possibility of misreading of MR images because of air or fluid in the epidural space after the injection. Therefore, we defined the characteristics of abnormal changes in MRI findings following an ESI in patients with low back pain. Methods: We reviewed the medical records of 133 patients who underwent MRI of the lumbar spine within 7 days after ESI between 2006 and 2015. All patients were administered an ESI using a 22-gauge Tuohy needle at the lumbar spine through the interlaminar approach. The epidural space was identified by the loss of resistance technique with air. Results: The incidences of abnormal changes in MRI findings because of ESI were 54%, 31%, and 25% in patients who underwent MRI at approximately 24 h, and 2 and 3 days after ESI, respectively. Abnormal MRI findings included epidural air or fluid, needle tracks, and soft tissue changes. Epidural air, the most frequent abnormal finding (82%), was observed in 41% of patients who underwent MRI within 3 days after injection. Abnormal findings due to an ESI were not observed in MR images acquired 4 days after ESI or later. Conclusions: Pain physicians should consider the possibility of abnormal findings in MR images acquired after epidural injection using the interlaminar approach and the loss of resistance technique with air at the lumbar spine.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.15 no.6
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• pp.463-470
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• 2022

Intravenous injection is widely used for patient treatment, including injection drugs, fluids, parenteral nutrition, and blood products, and is the most frequently performed invasive treatment for inpatients, including blood collection, peripheral catheter insertion, and other IV therapy, and more than 1 billion cases per year. Intravenous injection is one of the difficult procedures performed only by experienced nurses who have been trained in intravenous injection, and failure can lead to thrombosis and hematoma or nerve damage to the vein. Nurses who frequently perform intravenous injections may also make mistakes because it is not easy to detect veins due to factors such as obesity, skin color, and age. Accordingly, studies on auxiliary equipment capable of visualizing the venous structure of the back of the hand or arm have been published to reduce mistakes during intravenous injection. This paper is about the development of venous detection equipment that visualizes venous structure during intravenous injection, and the optimal combination was selected by comparing the brightness of acquired images according to the combination of near-infrared (NIR) LED and Filter with different wavelength bands. In addition, an image processing algorithm was derived to threshehold and making blood vessel part to green through grayscale conversion, histogram equilzation, and sharpening filters for clarity of vein images obtained through the implemented venous detection experimental module.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.15 no.6
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• pp.485-491
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• 2022

Intravenous injection is the most frequent invasive treatment for inpatients and is widely used for parenteral nutrition administration and blood products, and more than 1 billion procedures are used for peripheral catheter insertion, blood collection, and other IV therapy per year. Intravenous injection is one of the difficult procedures to be performed only by trained nurses with intravenous injection training, and failure can lead to thrombosis and hematoma or nerve damage to the vein. Accordingly, studies on auxiliary equipment capable of visualizing the vein structure of the back of the hand or arm are being published to reduce errors during intravenous injection. This study is a study on the performance difference according to the number of LEDs irradiating the 850nm wavelength band on a vein detector that visualizes the vein during intravenous injection. Four LED PCBs were produced by attaching NIR filters to CCD and CMOS camera lenses irradiated on the skin to acquire images, sharpen the acquired images using image processing algorithms, and project the sharpened images onto the skin. After that, each PCB was attached to the front end of the vein detector to detect the vein image and create a performance comparison questionnaire based on the vein image obtained for performance evaluation. The survey was conducted on 20 nurses working at K Hospital.

• Archives of Plastic Surgery
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• v.41 no.6
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• pp.647-653
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• 2014

Background Administration of growth factors has been associated with increased viability of composite grafts greater than 1-cm in diameter. Platelet-rich plasma (PRP) contains many of the growth factors studied. In this study, we evaluate the effect of PRP injection on composite graft viability and the proper time for injection. Methods A total of 24 New Zealand White rabbits were divided into four groups. Autologous PRP was injected into the recipient sites three days before grafting in group 1, on the day of grafting in group 2, and three days after grafting in group 3. Group 4 served as control without PRP administration. Auricular composite grafts of 3-cm diameter were harvested and grafted back into place after being rotated 180 degrees. Median graft viability and microvessel density were evaluated at day 21 of graft via macroscopic photographs and immunofluorescent staining, respectively. Results The median graft survival rate was 97.8% in group 1, 69.2% in group 2, 55.7% in group 3, and 40.8% in the control group. The median vessel counts were 34 (per ${\times}200$ HPF) in group 1, 24.5 in group 2, 19.5 in group 3, and 10.5 in the control group. Conclusions This study demonstrates that PRP administration is associated with increased composite graft viability. All experimental groups showed a significantly higher survival rate and microvessel density, compared with the control group. Pre-administration of PRP was followed by the highest graft survival rate and revascularization. PRP treatments are minimally invasive, fast, easily applicable, and inexpensive, and offer a potential clinical pathway to larger composite grafts.

• The Korean Journal of Pain
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• v.11 no.2
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• pp.194-200
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• 1998

Background: Effect of nitric oxide on the hyperalgesia induced by inflammation is controversial. We attempted to find out the peripheral effects of nitric oxide (NO) on hyperalgesia induced by Freund's complete adjuvant (FCA) induced inflammation. Methods: Male Sprague Dawley rats were divided into three groups; control, low dose NG-nitro-L-arginine methyl ester (L-NAME, 500 ug), high dose L-NAME (5 mg). Inflammation was induced by injecting 0.1 ml of FCA intraplantarly, which shows typical hyperalgesia within twelve hours after injection and maintained for about one week. Drugs were injected 2 hours before, just before, and 3, 6, 9, 12 hours after the injection of FCA. Effect of L-NAME on hyperalgesia was assessed by measuring mechanical hyperalgesia and spontaneous pain for 3 days. Results: When injected at the site of inflammation, L-NAME caused dose dependent reduction of spontaneous hyperalgesia. Mechanical hyperalgesia was also reduced by high dose L-NAME (p<0.05). After systemic injection of high dose L-NAME in the back, no significant difference was noticed. Conclusions: This suggest that L-NAME reduces FCA induced hyperalgesia via peripheral action.

• The Korean Journal of Pain
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• v.27 no.1
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• pp.35-42
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• 2014

Background: Epidural steroid injection (ESI) is one of the most common procedures for patients presenting low back pain and radiculopathy. However, there is no clear consensus on what constitutes appropriate steroid use for ESIs. To investigate optimal steroid injection methods for ESIs, surveys were sent to all academic pain centers and selected private practices in Korea via e-mail. Methods: Among 173 pain centers which requested the public health insurance reimbursements for their ESIs and were enrolled in the Korean Pain Society, 122 completed questionnaires were returned, for a rate of 70.5%; also returned were surveys from 39 academic programs and 85 private practices with response rates of 83.0% and 65.9%, respectively. Results: More than half (55%) of Korean pain physicians used dexamethasone for ESIs. The minimum interval of subsequent ESIs at the academic institutions (3.1 weeks) and the private practices (2.1 weeks) were statistically different (P = 0.01). Conclusions: Although there was a wide range of variation, there were no significant differences between the academic institutions and the private practices in terms of the types and single doses of steroids for ESIs, the annual dose of steroids, or the limitations of doses in the event of diabetes, with the exception of the minimum interval before the subsequent ESI.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.414-423
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• 2006

Many construction projects adopt grouting technology to prevent the leakage of groundwater or to improve the shear strength of the ground. Recognition as a feasible field procedure dates back to 1925, Since then, developments and field use have increased rapidly. According to improvement of grout materials, theoretical study on grout penetration characteristics is demanded. Fluid of grout always tends to flow from higher hydraulic potential to lower and the motion of grout is also a function of formation permeability. Viscosity of grout is changed by chemical action while grout moves through pores. Due to the increment of viscosity, permeability is decreased. Permeability is also reduced by grout particle deposits to the soil aggregates. In this thesis, characteristics of new cement grout material that is developed recently is studied: injectable volume of new grout material is tested in two different sizes of sands, and the method to calculate injectable volume of grout is suggested with consideration of change in viscosity and clogging phenomena. The calculated values are compared with injection test results. Viscosity of new grout material is found to be an exponential function of time. And lumped parameter $\theta$ of new grout material to be used for assessing deposition characteristics is estimated by comparing deposit theory with injection test results considering different soil types and different injection pressure.

• Reproductive and Developmental Biology
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• v.35 no.2
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• pp.167-174
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• 2011

Acute ischemic stroke results from sudden decrease or loss of blood supply to an area of the brain, resulting in a coinciding loss of neurological function. The antioxidant action of melatonin is an important mechanism among its known effects to protective activity during ischemic/reperfusion injury. The focus of this research, therapeutic efficacy of melatonin on recovery of neurological function following long term treatment in ischemic brain injured rats. Male Sprague-Dawley rats (n=40; 8 weeks old) were divided into the control group, and MCAo groups (Vehicle, MT7 : MCAo+ melatonin injection at 7:00, MT19 : MCAo+melatonin injection at 19:00, and MT7,19 : MCAo+melatonin injection at 7:00 and 19:00). Rat body weight and neurological function were measured every week for 8 weeks. After 8 weeks, the rats were anesthetized with a mixture of zoletil (40 mg/kg) and xylazine (10 mg/kg) and sacrificed for further analysis. Tissues were then collected for RNA isolation from brain tissue. Also, brain tissues were analyzed by histological procedures. We elucidated that melatonin was not toxic in vital organs. MT7,19 was the most rapidly got back to mild symptom on test of neurological parameter. Also, exogenous melatonin induces both the down-regulation of detrimental genes, such as NOSs and the up-regulation of beneficial gene, including BDNF during long term administration after focal cerebral ischemia. Melatonin treatment reduced the loss of primary motor cortex. Therefore, we suggest that melatonin could be act as prophylactic as well as therapeutic agent for neurorehabilitative intervention.

• Archives of Plastic Surgery
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• v.42 no.6
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• pp.677-685
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• 2015

Background The survival rate of grafted fat is difficult to predict, and repeated procedures are frequently required. In this study, the effects of the freezing period of harvested adipose tissue and the addition of human adipose tissue-derived stem cells (ASCs) on the process of fat absorption were studied. Methods Adipose tissue was obtained from patients who underwent a lipoaspirated fat graft. The fat tissue was cryopreserved at $-20^{\circ}C$ in a domestic refrigerator. A total of 40 nude mice were used. The mice in the experimental group received three different subcutaneous injections in the back: an injection of fresh fat and ASCs, an injection of fat that had been frozen for one month and ASCs, and an injection of fat that had been frozen for two months and ASCs. The control mice received fat grafts without ASCs. The mice were sacrificed at four or eight weeks after the procedure, and the grafted fat tissues were harvested. The extracted fat was evaluated using photographic analysis, volume measurements, and histological examination. Results In the control group, the fat resorption rates four weeks after transplantation in the grafts of fresh fat, fat that had been frozen for one month, and fat that had been frozen for two months were 21.14%, 22.46%, and 42.56%, respectively. In the experimental group, the corresponding resorption rates were 6.68%, 13.0%, and 33.9%, respectively. Conclusions ASCs can increase the fat graft survival rate. The use of ASCs in fat grafting can reduce the need for repeated fat grafts and provide good long term results.

• Design & Manufacturing
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• v.2 no.2
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• pp.29-32
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• 2008

A back light unit (BLU) is a key module of a thin film transistor liquid crystal display (TFT-LCD), frequently utilized in various mobile displays. In this study, we experimentally characterize transcription and optical properties of concave and convex microlens arrays (MLAs) of light guide plate (LGP) fabricated by injection molding with polycarbonate as a LGP substrate material. Nickel mold inserts were manufactured by electroforming on the MLA which was fabricated by the thermal reflow of photoresist microstructures patterned by UV-photolithography. For the case of convex microlens, the height of replicated microlens was less than that of the mold insert while maintaining almost the same microlens diameter of the mold insert as the location of the microlens is far from the gate. In contrast, for the concave microlens, the diameter of replicated microlens was larger than that of mold insert, while showing almost the same microlens height as the mold insert. From the optical examination of replicated convex and concave MLAs, it was found that a higher luminance of the LGP was achieved by the concave MLAs compared to the convex MLAs (about 30% enhancement in this case)due to the utilization of a larger amount of light provided by the light sources.