• Korean Chemical Engineering Research
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• v.62 no.1
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• pp.70-79
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• 2024

Raman analyzer is an analytical technique that utilizes the "Raman effect", which occurs when light is scattered by the inherent vibrations of molecules. It is used for molecular identification and composition analysis. In the natural gas industry, it is widely used in bunkering and tank lorry fields in addition to LNG export and import terminals. In this study, a LNG-specific Raman analyzer was installed and operated under actual field conditions to analyze the composition and principal properties (calorific value, reference density, etc.) of LNG. The measured LNG composition and calorific value were compared with those obtained by conventional gas chromatograph that are currently in operation and validated. The test results showed that the Raman analyzer provided rapid and stable measurements of LNG composition and calorific value. When comparing the calorific value, which serves as the basis for LNG transactions, with the results from conventional gas chromatograph, the Raman analyzer met the acceptable error criteria. Furthermore, the measurement results obtained in this study satisfied the accuracy criteria of relevant international standards (ASTM D7940-14) and demonstrated similar outcomes compared to large-scale international demonstration cases.

• Quality Improvement in Health Care
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• v.30 no.1
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• pp.33-43
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• 2024

Purpose:The acute hospital accreditation program launched in South Korea has shown positive effects on safety culture and quality of care. However, relative weights have not yet been investigated for accreditation criteria with a hierarchical structure. This study aimed to derive the relative weights of acute-care hospital accreditation criteria. Methods: We conducted an online survey using the analytic hierarchy process (AHP) technique to assess the validity, importance, and urgency of acute hospital accreditation criteria. The AHP online survey link was distributed in November 2022 after obtaining informed consent from 10 experts in hospital accreditation. Results: 'Basic value system' ranked highest, while 'patient care system' ranked second in terms of validity, importance, and urgency. 'Performance management system' had the lowest validity and urgency, while 'organizational management system' carried the lowest importance. Within the 'patient care system' domain, 'surgery and anesthesia sedation management' scored highest in validity and importance, and 'patient care' scored highest in urgency. 'Care delivery system and evaluation' received the lowest scores for all three aspects. In the 'organizational management system' domain, infection control ranked highest in terms of validity, importance, and urgency. The lowest validity was observed for 'management and organizational operation' and the lowest importance and urgency were noted for 'human resource management'. Conclusion: The weights for validity, importance, and urgency, as shown in each domain and chapter, and the number of measurable elements included, are largely inconsistent. This study will contribute to the development of the structure and scientific improvement of accreditation standards.

• Journal of Korean Tunnelling and Underground Space Association
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• v.26 no.3
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• pp.209-222
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• 2024

The Earth Pressure Balance (EPB) shield Tunnel Boring Machine (TBM) is widely used for underground tunnel construction for its advantages, such as eliminating the need for additional facilities compared to the slurry shield TBM, which requires Slurry Treatment Plant (STP). During EPB shield TBM excavation, a soil conditioning technique is employed to enhance the physical properties of the excavated soil by injecting additives, thus broadening the range of applicable ground conditions to EPB shield TBMs. This study explored the use of xanthan gum, a type of biopolymer, as an alternative to the commonly used polymer additive. Biopolymers, derived from biological sources, are fully biodegradable. In contrast to traditional polymers such as polyacrylic acid, which contain environmentally harmful components, xanthan gum is gaining attention as an eco-friendly material due to its minimal toxicity and environmental impact. Test conditions with similar workability were established through slump tests, and the rheological characteristics were assessed using a laboratory pressurized vane shear test apparatus. The experiments demonstrated that, despite exhibiting similar workability, the peak strength in the flow curve decreased with increasing the content of xanthan gum. Consequently, a correlation between the xanthan gum content and peak strength was established. Replacing the traditional polymers with xanthan gum could enable stable EPB shield TBM operation by reducing equipment load, in addition to offering environmental benefits.

• Journal of Industrial Convergence
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• v.22 no.7
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• pp.1-13
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• 2024

Among e-government services, the intelligent CCTV control platform is a screening control service that utilizes artificial intelligence to display major objects such as people, cars, etc. to control personnel when they appear on CCTV. The operation of an intelligent CCTV control platform is expected to improve the quality of life of citizens by enabling rapid response in the event of an emergency and increasing the resolution of complaints. In this study, the benefits of the intelligent CCTV control platform, a non-market good, were estimated by applying the contingent valuation method (CVM), a choice experiment technique, to estimate the average willingness to pay per household and calculate the social benefits. As a result of the analysis, the average willingness to pay per household was estimated to be KRW 6,908 per year, and the economic benefits for the country as a whole were estimated to be about KRW 150.4 billion per year. This study is of academic significance as it extends the application of CVM to the field of intelligent e-Government services. The Intelligent CCTV control platforms is being actively discussed, this study has practical implications in that the benefits were estimated in monetary value.

• Journal of Korean Neurosurgical Society
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• v.30 no.6
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• pp.688-698
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• 2001

Objectives : Parkinson's disease is a well-known neurodegenerative disease characterized by dopaminergic cell death in the substantia nigra. The reactive gliosis by activated astrocytes and microglias is no more regarded as a simple sequel of neuronal cell death. Microglial activation takes place in a stereotypic pattern with graded morphologic and functional(resting, activated and phagocytic) changes. In Parkinson's disease animal model, the degree of microglial activation along the nigro-striatal dopaminergic tract has not been studied intensively. The purpose of this study was to elucidate the characteristics of microglial reaction and to grade its degree of activation at substantia nigra and corpus striatum using 6-hydroxydopamine induced rat model of Parkinson's disease. Methods : Using Sprague-Dawley rat, parkinsonian model was made by 6-hydroxydopamine(OHDA) induced destruction of medial and lateral substantia nigra(SN). The rat was sacrificed 3-, 5-, 7-, 14- and 21-day-after operation. For control group, we injected saline with same manner and sacrificed 3-day after operation. With immunohistochemistry, we examined dopaminergic neuronal cells and microglial expression using tyrosine hydroxylase (TH) and OX-42 antibodies, respectively. Also we performed in situ hybridization for osteopontin, a possible marker of subset in activated microglia. Results : 1) In lesioned side of substantia nigra and corpus striatum, the TH immunoreactivity was markedly decreased in whole experimental groups. 2) Using optical densitometry, microglia induced immunoreactivity of OX-42 was counted at SN and corpus striatum. At SN, it was increased significantly on the lesioned side in control and all time-dependent experimental groups. At striatum, it was increased significantly in post lesion 3-day group only(p <0.05). Compared to control group, immunoreactivity of OX-42 on lesioned side was increased in groups, except post lesion 21-day group, at SN. Only post lesion 3-day group showed significance at striatum(p <0.05). Compared to SN region, immunoreactivity of OX-42 was much weaker in striatum. 3) Microscopically, the microglias showed typically different activation pattern. At SN, numerous phagocytic microglias were found at pars compacta and reticularis of lesion side. At striatum, no phagocytic form was found and the intensity of staining was much weaker. 4) At SN, the immunoreactivity of osteopontin showed definite laterality and it was markedly increased at pars compacta of lesion side with relatively short duration time. At striatum, however, it was not detected by in situ hybridization technique. Conclusion : The nigral 6-OHDA induced rat model of Parkinson's disease revealed several characteristic patterns of microglial reaction. At SN, microglias was activated shortly after direct neuronal damage and maintained for about three weeks. In contrast, despite of sufficient dopaminergic insufficiency at striatum, activation of microglias was trivial, and distinguished 3 day later. Antegrade slow neuronal degeneration is major pathophysiology in striatal dopaminergic deficiency. So, the acuteness of neuronal damage and consequential degree of neuronal degeneration may be important factor for microglial activation in neurodegenerative diseases such as Parkinson's disease. Additionally, osteopontin may be a possible marker for several subsets of activated microglia, possibly the phagocytic form.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.31 no.3
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• pp.243-248
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• 2009

Purpose: Rehabilitation of the edentulous posterior maxilla with dental implants often poses difficulty because of insufficient bone volume caused by pneumatization of the maxillary sinus and by crestal bone resorption. Sinus grafting technique was developed to increase the vertical height to overcome this problem. The present study was designed to evaluate the sinus floor augmentation with anorganic bovine bone (Bio-$cera^{TM}$) using histomorphometric and clinical measures. Patients and methods: Thirteen patients were involved in this study and underwent total 14 sinus lift procedures. Residual bone height was ${\geq}2mm$ and ${\leq}6mm$. Lateral window approach was used, with grafting using Bio-$cera^{TM}$ only(n=1) or mixed with autogenous bone from ramus and/or maxillary tuberosity(n=13). After 6 months of healing, implant sites were created with 3mm diameter trephine and biopsies taken for histomorphometric analysis. The parameters assessed were area fraction of new bone, graft material and connective tissue. Immediate and 6 months after grafting surgery, and 6 months after implantation, computed tomography (CT) was taken and the sinus graft was evaluated morphometric analysis. After implant installation at the grafted area, the clinical outcome was checked. Results: Histomorphometry was done in ten patients.Bio-$cera^{TM}$ particles were surrounded by newly formed bone. The graft particles and newly formed bone were surrounded by connective tissue including small capillaries in some fields. Imaging processing revealed $24.86{\pm}7.59%$ of new bone, $38.20{\pm}13.19%$ connective tissue, and $36.92{\pm}14.51%$ of remaining Bio-$cera^{TM}$ particles. All grafted sites received an implant, and in all cases sufficient bone height was achieved to install implants. The increase in ridge height was about $15.9{\pm}1.8mm$ immediately after operation (from 13mm to 19mm). After 6 months operation, ridge height was reduced about $11.5{\pm}13.5%$. After implant installation, average marginal bone loss after 6 months was $0.3{\pm}0.15mm$. Conclusion: Bio-$cera^{TM}$ showed new bone formation similar with Bio-$Oss^{(R)}$ histomorphometrically and appeared to be an effective bone substitute in maxillary sinus augmentation procedure with the residual bone height from 2 to 6mm.

• Applied Biological Chemistry
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• v.50 no.4
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• pp.245-252
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• 2007

FTA (fault tree analysis), an analytical method for system failure management, was employed in the management of faults in running PCR analysis. PCR is executed through several processes, in which the process of PCR machine operation was selected for the analysis by FTA. The reason for choosing the simplest process in the PCR analysis was to adopt it as a first trial to test a feasibility of the FTA approach. First, fault events-top event, intermediate event, basic events-were identified by survey on expert knowledge of PCR. Then those events were correlated deductively to build a fault tree in hierarchical structure. The fault tree was evaluated qualitatively and quantitatively, yielding minimal cut sets, structural importance, common cause vulnerability, simulation of probability of occurrence of top event, cut set importance, item importance and sensitivity. The top event was 'errors in the step of PCR machine operation in running PCR analysis'. The major intermediate events were 'failures in instrument' and 'errors in actions in experiment'. The basic events were four events, one event and one event based on human errors, instrument failure and energy source failure, respectively. Those events were combined with Boolean logic gates-AND or OR, constructing a fault tree. In the qualitative evaluation of the tree, the basic events-'errors in preparing the reaction mixture', 'errors in setting temperature and time of PCR machine', 'failure of electrical power during running PCR machine', 'errors in selecting adequate PCR machine'-proved the most critical in the occurrence of the fault of the top event. In the quantitative evaluation, the list of the critical events were not the same as that from the qualitative evaluation. It was because the probability value of PCR machine failure, not on the list above though, increased with used time, and the probability of the events of electricity failure and defective of PCR machine were given zero due to rare likelihood of the events in general. It was concluded that this feasibility study is worth being a means to introduce the novel technique, FTA, to the management of faults in running PCR analysis.

• Journal of Chest Surgery
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• v.36 no.10
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• pp.741-747
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• 2003

Background: Coronary artery bypass graf t (CABG) has been settled as most safe surgery among the open heart surgeries. However, in patients with cardiogenic shock, the emergency CABG has higher mortality than elective CABG. We analyzed thirty four patients who underwent emergency CABG and report the middle and long-term results. Material and Method: From June 1994 to December 2001, 34 patients who underwent emergency CABG at Kang-dong Sacred Heart Hospital were include in this study. On the basis of hospital databases and Out Patient Department (OPD) follow up data, preoperative diagnosis, risk factor, coronary artery anatomy, operation technique, postoperative mortality, complication, recurrence of symptom, and mid and long term mortality were analyzed retrospectively. Result: Indications for emergency CABG were 29 cardiogenic shocks (85.3%), 4 intractable chest pains (11.8%), and 1 polymorphic ventricular tachycardia (2.9%). Preoperative angiographic diagnoses were triple vessel disease in 16 (47.1%) and left main disease in 8 (23.5%) patients. We used saphenous vein grafts in 81 and left internal thoracic artery grafts in 14 anastomosis. The mean number of grafts per patients was 2.8$\pm$0.8. The mean aortic cross clamp time was 91.9$\pm$34.6 minutes and the mean cardiopulmonary bypass time was 262.7$\pm$198.3 minutes. Early mortality was 50% and the most common cause of early mortality was low cardiac output in 7 (20.6%) patients. The mean follow-up period was 30.9$\pm$35.7 months. There were no recurrences of symptom and late mortality. Conclusion: In the case of emergency operation, aggressive and proper management with drugs and IABP should be done for preoperative hemodynamic stability and early surgical intervention is the most important factor for patient salvage.

• Journal of Chest Surgery
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• v.35 no.8
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• pp.573-579
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• 2002

Background: In this study, the role and the surgical outcome of the modified Blalock-Taussig shunt in the treatment of the infants with cyanotic complex congenital heart diseases were investigated. Material and Method: Over the last 12 years, 105 modified BT shunts were performed in 100 infants. Postoperative course, shunt patency rate, complications, mortality and its risk factors were reviewed restrospectively. Result: The mean age at operation was 43.0$\pm$36.6 days. Sex ratio was 60:40(M:F). The postoperative oxygen saturations were lowest after mean duration of 11 hours after the shunt procedure. The operative mortality was 8%(8) with 3 late deaths. Causes of operative death included failure of maintenance of minimum oxygenation during the procedure(2), immediate postoperative shunt occlusion(2), respiratory failure(2), low cardiac output due to heart failure and pericardial effusion(2) and sepsis(2). Late deaths resulted from acute cardiac arrest during the follow up cardiac catheterization, hypoxic myocardial failure, and arrhythmia. Year of surgery, shunt size, age at operation, and complexity of the anomalies were not the risk factors for mortality. Six month shunt patency rate was 97% and overall patency rate was 96%. Postoperative complications comprised of shunt occlusion(6), phrenic nerve palsy(3), and wound infection(2). Conclusion: We demonstrated that modified Blalock-Taussig shunt was a useful tool to palliate the infants with complex cyanotic heart disease in whom early complete repair was not feasible with acceptable mortality and patency rate. An adequate postoperative management and a meticulous surgical technique may be key factors for the better results.

• Journal of Chest Surgery
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• v.42 no.3
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• pp.305-310
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• 2009

Background: The Ross procedure is known as a good surgical option for a young age group with aortic valve problems, but few reports on the Ross procedure are available in the Korean literature. This study is a review of our midterm results of 10 year experience with the pediatric Ross operation in Asan Medical Center. Material and Method: From March 1997 to October 2008, eighteen patients who were aged less than 16 years underwent the Ross procedure. There were 11 males and 7 females. The patients median age was 8.5 years (range: $0.5\sim14.0$). The aortic valve pathophysiology was 6 patients with aortic insufficiency, 4 patients with aortic stenosis, 7 patients with mixed aortic stenoinsufficiencey and 1 patient with infective endocarditis. The valve morphology was bicuspid in 11 and tricuspid in 7. All the patients were operated on with the root replacement technique. All the pumonic valves were replaced with an allograft except for one pericardial monocusp valve. The mean follow up duration was 52.8 months (range: 5.8$\sim$138.2 months). We reviewed the echocardiographic data with focusing on the, auto-graft dysfunction and reoperation. Result: There was no hospital mortality and late mortality. According to the last echocardiographic data, 2 autografts showed aortic regurgitation grade 2, 4 autografts showed aortic regurgitation grade 1 and the others were less than trivial. Reoperation of the pulmonic position conduit was performed 4 times in three patients. The rate of freedom from reoperation at 5 years was 72.2%. On the serial follow up, the Z-values of the aortic annulus/aortic sinus were changed from $1.6{\pm}1.7/0.9{\pm}1.7$ at preoperation to $1.8{\pm}1.6$(p=0.64)/$2.2{\pm}0.9$ (p=0.01) at the last follow-up. There was no significant relation between the growth of the neoaortic root and neoaortic insufficiency. Conclusion: Our midterm results of the Ross procedure in pediatric patients showed good autograft function and growth potential. Vet reoperation due to allograft dysfunction was a major concern.