• Journal of Korean Society on Water Environment
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• v.38 no.2
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• pp.103-112
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• 2022

A gold amalgam voltammetric microelectrode (GAVM) system was developed for the quantification of dissolved biogeochemical species, such as O₂, Fe²⁺, Mn²⁺, and HS^- in sediment porewater. Commercially available Ag/AgCl and platinum electrodes were used as the reference and counter electrode, respectively, and a gold amalgam microelectrode was fabricated in the laboratory using 150-um diameter gold wire and a borosilicate capillary tube with a 1.6-mm diameter. A portable potentiostat (Metrohm, DropSens) was used for the application of voltage sweeping and to acquire the electric current. For sediment profiling, a commercially available actuator was customized and modified. The analysis method used in the system used the most widely used analysis method among the electrochemical analysis currently used The GAVM system was successively calibrated with the species and applied to estuarine sediments. The porewater analysis showed that the oxygen concentration was decreased to zero at a depth of 0.6 mm, and maximum Mn²⁺ and Fe²⁺ concentrations of 50 uM and 20 uM were detected at 2 and 3-cm depths, respectively. Maximum HS^- concentrations of 10 uM were detected at 4 cm in the deeper sediments. The GAVM system was successfully developed and applied to the sediment and can be used to better understand biogeochemical reactions.

• Journal of Space Technology and Applications
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• v.2 no.2
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• pp.81-103
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• 2022

In this paper, the contents of the design and development process of the 6U micro-satellite Snipe (SNIPE, national name Toyosat; small scale magnetospheric and Ionospheric plasma experiment ), which was developed to observe the near-global space environment through polarization flight for the first time in Korea, were described. Snipe performs transversal flight to observe the Earth's surrounding space environment in three dimensions, and aims to simultaneously observe the space plasma density and temperature in the ionosphere, as well as temporal changes in the solar magnetic field and electromagnetic waves. In this way, it was developed by dividing it into a test certification model (EQM) and a flight model (FM) to perform the actual mission for at least six months, away from developing a cube satellite for short-term space technology verification or manpower training. Currently, Snipe, which has completed the development of a total of four FM and completed all space environment tests, is scheduled to launch 2023. In this paper, we introduce the design contents and development process of the Snipe satellite body ahead of launch, and hope that it will be a useful reference for the development of 6U-class micro-satellite for full-scale mission in Korea.

• Journal of Biomedical Engineering Research
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• v.43 no.2
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• pp.81-93
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• 2022

Proprioception training has been considered a secondary method to facilitate postural control ability. This study investigated the effects of two different proprioception training methods - the proprioceptive neuromuscular facilitation (PNF) and visual feedback-based joint position and force reproduction (VF) - on postural control advancements. Sixteen healthy people volunteered for this study, and they randomly grouped two. Each group participated in the PNF and VF training for three weeks. We evaluated each subject's proprioception levels and balance ability before and after the training. We used a clinometer and electromyogram (EMG) for VF training. The joint position reproduction test was also used to evaluate the position and force aspects of the proprioception level. We analyzed the trajectory of the center of pressure (COP) while subjects were standing on the firm floor and balance board with one leg using a pressure mat. The improvement of the position aspect of the proprioception level of the VF group (4.93±4.74°) was larger than that of the PNF group (-0.43±2.08°) significantly (p=0.012). The improvement of the anterior-posterior COP velocity of the PNF group (0.01±0.01 cm/s) was larger than that of VF group(0.002±0.01 cm/s) significantly (p=0.046). Changes of position error in the PNF group (rho=0.762, p=0.028) and tibialis anterior force reproduction error in the VF group showed a significantly strong relationship with balance ability variables. These results showed that different PNF and VF have different effects on improving two aspects of proprioception and their relationship with the balance ability. Therefore, these results might be useful for selecting proprioception or balance rehabilitation considering the clinical and patients' situation.

• Journal of the Korean Orthopaedic Association
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• v.54 no.3
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• pp.203-210
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• 2019

The aim of this review was to evaluate minimally invasive lateral lumbar interbody fusion on the latest update. Lumbar interbody fusion was introduced recently. This study performed, a literature review of the indications, clinical outcomes, fusion rate, and complications regarding recently highlighted minimally invasive lateral lumbar interbody fusion. The indications of lateral lumbar interbody fusion are similar to the conventional anterior and posterior interbody fusion in degenerative lumbar diseases. In particular, lateral lumbar interbody fusion is an effective minimally invasive surgery in spinal stenosis, degenerative spondylolisthesis, degenerative adult deformity, degenerative disc disease and adjacent segment disease. In addition, the clinical outcomes and fusion rates of lateral lumbar interbody fusion are similar compared to conventional lumbar fusion. On the other hand, non-specific complications including hip flexor weakness, nerve injury, vascular injury, visceral injury, cage subsidence and pseudohernia have been reported. Lateral lumbar interbody fusion is a very useful minimally invasive surgery because it has advantages over conventional anterior and posterior interbody fusion without many of the disadvantages. Nevertheless, nonspecific complications during lateral lumbar interbody fusion procedure remain a challenge to be improved.

• Journal of Chest Surgery
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• v.42 no.2
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• pp.206-213
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• 2009

Background: Previous series have suggested that younger patients with primary lung cancer exhibit a more aggressive disease course with a worse prognosis, as compared to older patients, although this issue is still debatable. Material and Method: We reviewed the medical records of 79 patients (32 patients 50 years and younger (Group I) and 47 patients 70 years and older (Group II)) who underwent curative resection for primary lung cancer between July 2000 and June 2008. Result: The median age of the patients was 46.5 years in Group I and this was 73 years in Group II. The older patients were more likely to have major comorbidities (44% versus 77%, respectively; p=0.003). Histological examinations identified that the minor histological types (excluding non-small cell lung cancer (NSCLC)) were predominantly found in the Group I patients (16% versus 2%, respectively; p=0.037). For the TNM staging of the NSCLC, with excluding the minor histologic types, a higher proportion of patients had stage III disease in Group I (33% versus 13%, respectively; p=0.038). There was no significant difference in major morbidity (16% versus 30%, respectively; p=0.148) and operative mortality (0% versus 4.3%; p=0.512) between the groups. The mean follow-up interval was 33 months (range: $1{\sim}98$ months) for patients in both groups. For the patients with NSCLC, the five-year overall survival rate was 52.3% for Group I and 53.7% for Group II (p=0.955). The rate of freedom from recurrence at five years was significantly lower for the Group I patients than for the Group II patients (39.4% versus 70.4%, respectively; p=0.027), and only being a member of Group I impacted recurrence, based on the Cox proportional hazard analysis (p=0.034). Of the patients who had recurrence, four patients in Group I underwent aggressive surgical treatment. All of these patients exhibited long-term survival (range: $46{\sim}87$ months). Conclusion: In our study, the early outcome and long-term survival were similar for the younger and older patients after curative resection of primary lung cancer. However, we think that younger patients require meticulous follow-up as they had a tendency to proceed to surgery with advanced stage disease, a higher recurrence rate than did the older patients and the survival rates were improved, even for the recurred cases, with early aggressive treatment.

• Journal of Chest Surgery
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• v.37 no.4
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• pp.356-363
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• 2004

Esophageal cancer is an aggressive disease with a poor prognosis. Recently, every effort has been made to improve the long term survival, but the general prognosis for patients with this disease remains poor. In this study, we reviewed 8 years of experiences with esophageal cancer patients managed in our department at Dong-A University Hospital and evaluated the effectiveness of cervical lymph node dissection performed selectively. Material and Method: From January 1995 to August 2003, 70 patients underwent esophagectomy for esophageal cancer in our department. Among them, 51 patients who underwent curative resection, had no double primary tumors and no neoadjuvant therapy were analyzed retrospectively. In most patients, intrathoracic esophagectomy and cervical esophago-gastrostomy was performed. Since 1997, 3-field lymph node dissection was performed selectively. Result: There were 46 men and 15 women. The median age was 60 years. The tumor was located in the upper third part in 10 patients (19%), middle third in 21 (41%), and lower third in 20 (40%). Majority of the patients (90%) had squamous cell carcinoma. Cervical anastomosis was made in 41 patients, and intrathoracic anastomosis in 10. 2-field lymph node dissection was done in 40 patients, and 3-field lymph node dissection in 11. The pathologic staging were as follows: stage I in 9 patients (17.6%), IIA in 20 (39.2%), IIIB in 7 (13.7%), III in 11 (21.6%), IVA in 2 (3.9%), and IVB in 2 (3.9%). The in-hospital mortality was 3.9% (2 patients) and complications occurred in 24 patients (47%). Overall actuarial 1, 3, and 5-year survival rates were 74.4%, 48.4%, and 48.4% including operative mortality. The 4-year survival rate did not differ significantly between 3-field lymph node dissection group (50.5%) and 2-field lymph node dissection group (48.9%). In 3-field lymph node dissection group, the respiratory complications were more frequent and operative time was significantly longer. Conclusion: We think that curative resection for esophageal cancer can be performed with acceptable mortality, and aggressive surgical approach may improve the long term survival. even for advanced stages. Effectiveness of 3-field lymph node dissection needs further investigations.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.2
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• pp.120-128
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• 2009

Purpose: Early detection of recurrence is an important factor for long term survival of patients with colorectal cancer. Measurement of serum levels of CEA, CA 19-9, CT and PET/CT has been commonly used in the postoperative surveillance of colorectal cancer. The purpose of this study was to compare the diagnostic ability of PET/CT, tumor marker and CT for recurrence in colorectal cancer patients after treatment. Materials and Methods: F-18 FDG PET/CT imaging was performed in 189 colorectal cancer patients who underwent curative surgical resection and/or chemotherapy. Measurement of serum levels of CEA, CA 19-9 and CT imaging were performed within 2 months of PET/CT examination. Final diagnosis of recurrence was made by biopsy, radiologic studies or clinical follow-up for 6 months after each study. Results: Overall sensitivity, specificity of PET/CT was 94.7%, 91.1%, while those of serum CEA were 44.7% and 97.3%, respectively. Sensitivity and specificity were 94.2%, 90.4% for PET/CT and better than those of combined CEA and CA 19-9 measurement(52.1%, 88.5%) in 174 patients measured available both CEA and CA 19-9 data. In 115 patients with both tumor markers and CT images available, PET/CT showed similar sensitivity but higher specificity(92.9%, 91.3%) compared to combination of tumor markers and CT images(92.9%, 74.1%). Conclusion: PET/CT was superior for detection of recurred colorectal cancer patients compared with both CEA, CA 19-9, and even with combination of both tumor markers and CT. Therefore PET/CT could be used as a routine surveillance examination to detect recurrence or metastasis of colorectal cancer.

• Journal of Life Science
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• v.25 no.1
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• pp.21-28
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• 2015

Genetic polymorphisms of adipocyte determination and differentiation factor 1 (ADD1) gene were screened in Hanwoo and Jeju Black cattle-derived commercial (JBC-DC) populations. The ADD1 genotypes were determined using the presence/absence of 84-bp fragment at intron 7 region. The association of ADD1 genotypes for economic traits was examined in both populations. In the Hanwoo steers, ADD1 D/- carcasses showed significantly thicker backfat levels than those from WW (p<0.05). However, the thickest level of backfat appeared in WD heterozygotes, whereas thicker backfat did not appear in DD homozygotes in the JBC-DC population (p<0.05), leading to the supposition that synergic effects of alleles W and D increase backfat deposition. On the other hand, there was no association between the ADD1 genotypes and intramuscular fat deposition measured as meat quality index and marbling score. From these results, we concluded that the bovine ADD1 affected the backfat in subcutaneous tissue, rather than intramuscular fat in muscle tissue. In addition, the DD animals showed higher levels of meat color than those from W/- (p<0.05). Interestingly, a highly significant difference was found between the genotypes and carcass weights only in the JBC-DC population, and D/- animals were heavier by more than 38 kg than those from WW (p<0.001). The results of this study reveal faster growth rate and differences in steer productivity according to genotypes of the ADD1 gene. These findings demonstrate that ADD1 genotypes may effectively function as molecular genetic markers for the improvement of Hanwoo and Jeju Black cattle-related crossbreeding systems.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.55 no.1
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• pp.1-7
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• 2010

Stress from excess water is one of the most harmful limiting factor in soybean yield during the wet season under the climate conditions. Soybean is very sensitive to excess water compare to other crops. This experiment was carried out to identify the growth responses for establishing a screening system related to waterlogging tolerance in soybean from 2003 to 2004. The root dry weight accumulation rate of per day for 21 days after waterlogging at V5 stage was the highest in Pungsannamulkong (47~56% of control) and was the lowest in Jangyeobkong (26~27% of control). The nodules dry weight recovery rate was the highest in Pungsannamulkong (83~91% of control), while the lowest in Myungjunamulkong (48~66% of control). After waterlogging, recovery rate of roots was high, which increased the root/shoot ratio of Pungsannamulkong, which also produced significantly more adventitious roots than in Jangyeobkong. The percentage of adventitious roots fresh weight to the total roots fresh weight was the lowest in Myungjunamulkong (14%), while the highest in Pungsannamulkong (38%). This results implies that the water and nutrients absorbing ability of Pungsannamulkong is more higher than that of Myungjunamulkong during late growth period.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.31 no.1
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• pp.98-107
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• 2013

Big and old trees in the scenic spots with the attributes of remote villas are vulnerable to man-made damages and very sensitive to the external environment such as soil conditions, so the corresponding management plans are required. Thus this study has been conducted to survey the big and old trees in the scenic remote villas and suggest the ideal management plans. The results can be summarized as follows. First, regarding the tree heath above the ground, transformation of tree, death of branches, and death of barks are closely related to tree vigor. Particularly, the areas receiving many visitors require prompt countermeasures against the dried and dead tress above the ground and the areas in which dried and dead tress occurred and also the safety measures for the visitors and facilities. Second, regarding the soil environment, visitor traffic is closely related to the tree vigor. In 15 remote villa gardens, 64% of trees are exposed to heavy traffic and the tree vigor has declined due to an increase of visitor. Thus, there is a need to give positive consideration the installation of the complementary facilities and the plantation of herbal plants in the congested areas to form the ground surface that can tolerate the heavy visitor traffic. Third, remote gardens are in general located adjacent to ponds and mountain streams and thus the trees in the waterfront areas require the prompt countermeasures against the decline of growth due to the excess-moisture in the soil. Further the blockage of the sewage system due to the heavy rains dampens the surrounding soil, which results in lethal damages to the trees. Thus, there is a need of the maintenance of the waterfront areas and sewage system before and after the rainy season. In addition, there is a need to establish medium-long term management polices through the recognition of the importance of the main trees of remote villa gardens in scenic spots and prepare the tree management manual depending on the attributes of the corresponding areas. I strongly suggest making manuals for the systematic management as well as the extensive PR activities and education for the preservation of tress on a long-term basis; and furthermore securing the budget and manpower for the research and development of a systematic management system.