• Journal of Food Hygiene and Safety
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• v.32 no.6
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• pp.507-512
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• 2017

There has been increasing concern regarding misuse of disinfectants and sanitizers such as ethanol, sodium hypochlorite, and hydrogen peroxide for food contact surfaces in the food industry. Examining the efficacy of the concentration of currently used disinfectants and sanitizers is urgently required in the Korean society. This study aimed to develop predictive reduction models for Escherichia coli and Staphylococcus aureus in suspension, as a function of $ClO_2$ (chlorine dioxide) and contact time using response surface methodology. E. coli ATCC 10536 and S. aureus ATCC 6538 (initial inoculum, 8-9 log CFU/mL) in tryptic soy broth were treated with different concentrations of $ClO_2$ (5, 20, and 35 ppm) for different contact times (1, 3, and 5 min) following a central composite design. The polynomial reduction models for $ClO_2$ on E. coli and S. aureus were developed under the clean condition. E. coli reduction by 35 ppm $ClO_2$ for 1, 3, and 5 min was 2.49, 2.70, and 3.65 log CFU/mL, respectively. Also, S. aureus reduction by 35 ppm $ClO_2$ for 1, 3, and 5 min was 4.59, 5.25, and 5.81 log CFU/mL, respectively. The predictive response polynomial models developed were $R=0.43231-0.056492^*X_1-0.097771^*X_2+9.24167E-003^*X_1^*X_2+3.06333E-003^*X_1{^2}$ ($R^2=0.98$) on E. coli and $R=1.10542-0.20896^*X_1-0.046062^*X_2+8.30000E-003^*X_1^*X_2+8.73300E-003^*X_1{^2}$ ($R^2=0.99$) on S. aureus, where R was the bacterial reduction (log CFU/mL), $X_1$ was the concentration and $X_2$ was the contact time. Our predictive reduction models should be validated in developing the optimal concentration and contact time of $ClO_2$ for inhibiting E. coli and S. aureus on food contact surfaces.

• Korean Journal of Remote Sensing
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• v.38 no.6_3
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• pp.1827-1836
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• 2022

Disasters that occur unexpectedly are difficult to predict. In addition, the scale and damage are increasing compared to the past. Sometimes one disaster can develop into another disaster. Among the four stages of disaster management, search and rescue are carried out in the response stage when an emergency occurs. Therefore, personnel such as firefighters who are put into the scene are put in at a lot of risk. In this respect, in the initial response process at the disaster site, robots are a technology with high potential to reduce damage to human life and property. In addition, Light Detection And Ranging (LiDAR) can acquire a relatively wide range of 3D information using a laser. Due to its high accuracy and precision, it is a very useful sensor when considering the characteristics of a disaster site. Therefore, in this study, development and experiments were conducted so that the robot could perform real-time monitoring at the disaster site. Multi-sensor module was developed by combining LiDAR, Inertial Measurement Unit (IMU) sensor, and computing board. Then, this module was mounted on the robot, and a customized Simultaneous Localization and Mapping (SLAM) algorithm was developed. A method for stably mounting a multi-sensor module to a robot to maintain optimal accuracy at disaster sites was studied. And to check the performance of the module, SLAM was tested inside the disaster building, and various SLAM algorithms and distance comparisons were performed. As a result, PackSLAM developed in this study showed lower error compared to other algorithms, showing the possibility of application in disaster sites. In the future, in order to further enhance usability at disaster sites, various experiments will be conducted by establishing a rough terrain environment with many obstacles.

• Journal of the Korean Society of Radiology
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• v.82 no.3
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• pp.654-669
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• 2021

Purpose To evaluate the accuracy of MRI in predicting the pathological complete response (pCR) and the residual tumor size of breast cancer after neoadjucant chemotherapy (NAC), and to determine the factors affecting the accuarcy. Materials and Methods Eighty-eight breast cancer patients who underwent surgery after NAC at our center between 2010 and 2017 were included in this study. pCR was defined as the absence of invasive cancer on pathological evaluation. The maximum diameter of the residual tumor on post-NAC MRI was compared with the tumor size of the surgical specimen measured pathologically. Statistical analysis was performed to elucidate the factors affecting pCR and the residual tumor size-discrepancy between the MRI and the pathological measurements. Results The pCR rate was 10%. The diagnostic accuracy of MRI and the area under the curve for predicting pCR were 90.91% and 0.8017, respectively. The residual tumor sizes obtained using MRI and pathological measurements showed a strong correlation (r = 0.9, p < 0.001), especially in patients with a single mass lesion (p = 0.047). The size discrepancy between MRI and the pathological measurements was significantly greater in patients with the luminal type (p = 0.023) and multifocal tumors/non-mass enhancement on pre-NAC MRI (p = 0.047). Conclusion MRI is an accurate tool for evaluating pCR and residual tumor size in breast cancer patients who receive NAC. Tumor subtype and initial MRI features affect the accuracy of MRI.

• Tuberculosis and Respiratory Diseases
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• v.46 no.5
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• pp.685-696
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• 1999

Background : Idiopathic pulmonary fibrosis (IPF) is a diffuse inflammatory and fibrosing process that occurs within the interstitium and alveolus of the lung with invariably poor prognosis. The major problem in management of IPF results from the variable rate of disease progression and the difficulties in predicting the response to therapy. The purpose of this retrospective study was to evaluate the short-term efficacy of steroid and immunosuppressive therapy for IPF and to identify the pre-treatment determinants of favorable response. Method : Twenty patients of IPF were included. Diagnosis of IPF was proven by thoracoscopic lung biopsy and they were presumed to have active progressive disease. The baseline evaluation in these patients included clinical history, pulmonary function test, bronchoalveolar lavage (BAL), and chest high resolution computed tomography (HRCT). Fourteen patients received oral prednisolone treatment with initial dose of 1mg/kg/day for 8 to 12 weeks and then tapering to low-dose prednisolone (0.25mg/kg/day). Six patients who previously had experienced significant side effects to steroid received 2mg/kg/day of oral cyclophosphamide with or without low-dose prednisolone. Follow-up evaluation was performed after 6 months of therapy. If patients met more than one of followings, they were considered to be responders : (1) improvement of more than one grade in dyspnea index, (2) improvement in FVC or TLC more than 10% or improvement in DLco more than 20% (3) decreased extent of disease in chest HRCT findings. Result : One patient died of extrapulmonary cause after 3 month of therapy, and another patient gave up any further medical therapy due to side effect of steroid. Eventually medical records of 18 patients were analyzed. Nine of 18 patients were classified into responders and the other nine patients into nonresponders. The histopathologic diagnosis of the responders were all nonspecific interstitial pneumonia (NSIP) and that of nonresponders were all usual interstitial pneumonia (UIP) (p<0.001). The other significant differences between the two groups were female predominance (p<0.01), smoking history (p<0.001), severe grade of dyspnea (p<0.05), lymphocytosis in BAL fluid ($23.8{\pm}16.3%$ vs $7.8{\pm}3.6%$, p<0.05), and less honeycombing in chest HRCT findings (0% vs $9.2{\pm}2.3%$, p<0.001). Conclusion : Our results suggest that patients with histopathologic diagnosis of NSIP or lymphocytosis in BAL fluid are more likely to respond to steroid or immunosuppressive therapy. Clinical results in large numbers of IPF patients will be required to identify the independent variables.

• Korean Journal of Food Science and Technology
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• v.27 no.3
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• pp.428-438
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• 1995

The gelatinization properties of corn and waxy corn starch doughs were examined at various moisture contents, heating temperatures and heating times. The onset temperatures of gelatinization with 1% CMC using Brabender Amylograph were $64^{\circ}C$ for both corn and waxy corn starch. In the gelatinization properties using DSC, onset temperature$(T_o)$, maximum peak temperature$(T_p)$, completion temperature$(T_c)$ and enthalpy of the corn starch were $68.15^{\circ}C,\;74.01^{\circ}C,\;85.65^{\circ}C$ and $3.2\;cal/gram$ respectively. While those of the waxy corn starch were $68.24^{\circ}C,\;75.43^{\circ}C,\;93^{\circ}C$ and $4.2\;cal/gram$ respectively. In enzymatic analysis, when the moisture content increased from 36% to 52% and heating temperature from $60^{\circ}C$ to $100^{\circ}C$, the gelatinization degree of starch dough increased from about 10% to about 62%. The gelatinization degree of waxy corn starch dough was $15{\sim}20%$ higher than that of corn starch dough under the same gelatinization conditions. The regression equations of gelatinization degree (Y) of starch dough in the range of $36{\sim}52%$ moisture content $(X_1)\;60{\sim}100^{\circ}C$ heating temperature $(X_2)\;and\;0{\sim}2.0$ min heating time $(X_3)$ were examined using response surface analysis. The regression equation of corn starch dough was: $Y=28.659+8.638\;X_}+15.675\;X_2+7.770\;X_3-1.620\;{X_1}^2+10.790\;X_1X_2-4.220\;{X_2}^2+0.510\;X_1X_3+1.980\;X_2X_3-6.850\;{X_3}^2\;(R^2=0.9714)$ and that of waxy corn starch dough was: $Y=32.617+12.535\;X_1+20.470\;X_2+8.608\;X_3+4.093\;{X_1}^2+13.550\;X_1X_2-4.467\;{X_2}^2+1.560\;X_1X_3+2.160\;X_2X_3-9.527\;{X_3}^2$\;(R^2=0.9621)$. As the moisture content, heating temperature and heating time increased, the reaction rate constant(k) of gelatinization increased. The greatest reaction rate constant was observed at initial 0.5 min heating time of 1st gelatinization stage. At the heating temperature of $90^{\circ}C$, gelatinization of starch dough was completed almost in the initial 0.5 min heating time. The reaction rate constant of waxy corn starch dough was higher than that of corn starch dough under the same gelatinization conditions. At the 52% moisture content, the regression equation between reaction rate constant(k) and heating temperature(T) for corn starch dough was $log\;k=11.1140-4.1226{\times}10^3(1/T)$ (r=-0.9520) and that of waxy corn starch dough was $log\;k=10.1195-3.7090{\times}10^3(1/T)$ (r=-0.9064).

• Tuberculosis and Respiratory Diseases
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• v.42 no.6
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• pp.871-877
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• 1995

Background: The index which could predict the prognosis of critically ill patients is needed to find out high risk patients and to individualize their treatment. The APACHE III scoring system was established in 1991, but there has been only a few studies concerning its prognostic value. We wanted to know whether the APACHE III scores have prognostic value in discriminating survivors from nonsurvivors in sepsis. Methods: In 48 patients meeting the Bones criteria for sepsis, we retrospectively surveyed the day 1(D1), day 2(D2) and day 3(D3) scores of patients who were admitted to intensive care unit. The scores of the sepsis survivors and nonsurvivors were compared in respect to the D1 score, and also in respect to the changes of the updated D2 and D3 scores. Results: 1) Of the 48 sepsis patients, 21(43.5%) survived and 27(56.5%) died. The nonsurvivors were older($62.7{\pm}12.6$ vs $51.1{\pm}18.1$ yrs), presented with lower mean arterial pressure($56.9{\pm}26.2$ vs $67.7{\pm}14.2\;mmHg$) and showed greater number of multisystem organ failure($1.2{\pm}0.8$ vs $0.2{\pm}0.4$) than the survivors(p<0.05, respectively). There were no significant differences in sex and initial body temperature between the two groups. 2) The D1 score was lower in the survivors (n=21) than in the nonsurvivors ($44.1{\pm}14.6$, $78.5{\pm}18.6$, p=0.0001). The D2 and D3 scores significantly decreased in the survivors (D1 vs D2, $44.1{\pm}14.6$ : $37.9{\pm}15.0$, p=0.035; D2 vs D3, $37.9{\pm}15.0$ : $30.1{\pm}9.3$, p=0.0001) but showed a tendency to increase in the nonsurvivors (D1 vs D2 (n=21), $78.5{\pm}18.6$ : $81.3{\pm}23.0$, p=0.1337; D2 vs D3 (n=11), $68.2{\pm}19.3$ : $75.3{\pm}18.8$, p=0.0078). 3) The D1 scores of 12 survivors and 6 nonsurvivors were in the same range of 42~67 (mean D1 score, $53.8{\pm}10.0$ in the survivors, $55.3{\pm}10.3$ in the nonsurvivors). The age, sex, initial body temperature, and mean arterial pressure were not different between the two groups. In this group, however, D2 and D3 was significantly decreased in the survivors(D1 vs D2, $53.3{\pm}10.0$ : $43.6{\pm}16.4$, p=0.0278; D2 vs D3, $43.6{\pm}16.4$ : $31.2{\pm}10.3$, p=0.0005), but showed a tendency to increase in the nonsurvivors(D1 vs D2 (n=6), $55.3{\pm}10.3:66.7{\pm}13.9$, p=0.1562; D2 vs D3 (n=4), $64.0{\pm}16.4:74.3{\pm}18.6$, p=0.1250). Among the individual items of the first day APACHE III score, only the score of respiratory rate was capable of discriminating the nonsurvivors from the survivors ($5.5{\pm}2.9$ vs $1.9{\pm}3.7$, p=0.046) in this group. Conclusion: In sepsis, nonsurvivors had higher first day APACHE III score and their updated scores on the following days failed to decline but showed a tendency to increase. Survivors, on the other hand, had lower first day score and showed decline in the updated APACHE scores. These results suggest that the first day and daily updated APACHE III scores are useful in predicting the outcome and assessing the response to management in patients with sepsis.

• Radiation Oncology Journal
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• v.19 no.2
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• pp.87-94
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• 2001

Purpose : To evaluate the role of LINAC-based stereotactic radiosurgery (SRS) in the management of meningiomas, we reviewed clinical response, image response, neurological deficits for patients treated at our institution. Methods and materials : Between February 1995 and December 1999, twenty-six patients were treated with SRS. Seven patients had undergone prior resection. Nineteen patients received SRS as the initial treatment. There were 7 male and 19 female patients. The median age was 51 years (range, $14\~67\;years$). At least one clinical symptom presented at the time of SRS in 17 patients and cranial neuropathy was seen in 7 patients. The median tumor volume was $4.7\;cm^3\;(range,\;0.7\~16.5\;m^3)$. The mean marginal dose was 15 Gy (range, $10\~20\;Gy$), delivered to the $80\%$ isodose surface (range, $46\~90\%$). The median clinical and imaging follow-up periods were 27 months (range, 1-71 months) and 25 months (range, $1\~52\;months$), respectively. Results : Of 14 patients who had clinical follow-up of one year or longer, thirteen patients $(93\%)$ were improved clinically at follow-up examination. Clinical symptom worsened in one patient at 4 months after SRS as a result of intratumoral edema, who underwent surgical resection at 7 months. OF 14 patients who had radiologic follow-up of one year or longer, tumor volume decreased in 7 patients $(50\%)$ at a median of 11 months (range, $6\~25\;months$), remained stable in 6 patients $(43\%)$, and increased in one patient $(7\%)$, who underwent surgical resection at 44 months. New radiation-induced neurological deficits developed in six patients $(23\%)$. Five patients $(19\%)$ had transient neurological deficits, completely resolved by conservative treatment including steroid therapy. Radiation-induced brain necrosis developed in one patient $(3.8\%)$ at 9 months after SRS who followed by surgical resection of tumor and necrotic tissue. Conclusions : LINAC-based SRS proves to be an effective and safe management strategy for small to moderate sized meningiomas, inoperable, residual, and recurrent, but long-term follow-up will be necessary to fully evaluate its efficacy. To reduce the radiation-induced neurological deficit for large size meningioma and/or in the proximity of critical and neural structure, more delicate treatment planning and optimal decision of radiation dose will be necessary.

• Childhood Kidney Diseases
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• v.3 no.1
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• pp.11-19
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• 1999

Purpose: MCNS is found in approximately $85\%$ of the idiopathic nephrotic syndrome in children and shows good prognosis with initial steroid therapy. MCNS most commonly appears between the ages of 2 and 10 yr. But the incidence and prognosis in adolescent MCNS are different from those found in young children; the prognosis and the response to therapy is unfavorable with increasing ages. So we compared the prevalence and the clinical manifestations of adolescent MCNS with that of childhood MCNS for management of adolescent MCNS. Methods: We conducted a retrospective study with a review of histopathologic findings and clinical manifestations of the 216 cases with MCNS which were divided into children group and adolescent group by their age of onset; under 12 years(childhood) and between 12-18 years(adolescent). Results: 1) The number of childhood idiopathic nephrotic syndrome was 245 cases, and that of adolescent idiopathic nephrotic syndrome was 55 cases. 188 cases($77\%$) showed MCNS, 30 cases($12\%$) FSGS, 4 cases($1.6\%$) MSPCN in childhood idiopathic nephrotic syndrome; 28 cases($51\%$) showed MCNS, 12 cases($22\%$) FSGS in adolescent idiopathic nephrotic syndrome. 2) The mean onset age was $7.53{\pm}5.5$ years, and the male to female ratio was 3.8:1 in childhood onset and 2.5:1 in adolescent onset with male predominance. 3) Hematuria was associated with $17\%$ of childhood onset and $39.3\%$ of adolescent onset disease(P=0.005). Hypertension appeared in $0.5\%\;and\;7\%$ in each group without significant difference between the groups. 4) 24 hour urine protein, SPI, albumin, BUN, cholesterol level showed no significant difference. 5) The response of childhood onset and adolescent onset MCNS to steroid therapy showed complete remission in $11.7\%\;&\;14.7\%$, infrequent relapsing in $29.2\%\;&\;28.5\%$, frequent relapsing in $23.9\%\;&\;14.7\%$, steroid dependent in $21.8\%\;&\;28.6\%$ each. Steroid resistant showed $13.3\%\;&\;14.7\%$ with no significance. 6) Immunosuppresant therapy was performed $57\%$ in childhood onset and $65\%$ in adolescent onset. 7) Mean number of relapse and duration from onset to first relapse showed no significance between two groups. Conclusion : Our results indicate that the incidence of hematuria, the rate of steroid dependent and frequent relapsing, and the recurrence rate were higher in adolescent MCNS; showed poorer steroid responsiveness and prognosis. Our data also point to the need for a more aggressive therapy to treat and make recommendations for the adolescent population as a whole.

• Tuberculosis and Respiratory Diseases
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• v.48 no.4
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• pp.530-542
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• 2000

Background : Nonspecific interstitial pneumonia (NSIP) has been reported recently to have shown much better response to medical treatment and better prognosis compared with idiopathic UIP. However, clinical characteristics of idiopathic NSIP discriminating it from UIP have not been clearly defined. Method : Among 120 patients with biopsy-proven diffuse interstitial lung diseases admitted to the Samsung Medical Center between July 1996 and March 2000, 18 patients with idiopathic NSIP were included in this study. Retrospective chart review and radiographic analysis were performed. Results : 1) At diagnosis, 17 patients were female and the average age was $55.2{\pm}8.4$ years (44~73 years). The average duration from development of respiratory symptom to surgical lung biopsy was $9.9{\pm}17.1$ months. Increase in bronchoalveolar lavage fluid lymphocytes ($23.0{\pm}13.1%$) was noted. On HRCT, ground glass and irregular linear opacity were observed, but honeycombing was absent in all patients. 2) Corticosteroids were initially given to 13 patients, but the medication was stopped in 3 patients due to severe side effects. Further medical therapy was not possible in 1 patient who experienced streroid-induced psychosis. Herpes zoster (n=3), tuberculosis (n=1), avascular necrosis of the hip (n=1), cataract (n=2) and diabetes mellitus (n=1) developed during prolonged corticosteroid administration. Of the 7 patients receiving oral cyclophosphamide therapy, hemorrhagic cystitis hindered one patient from continuing with the medication. 3) After medical treatment, 14 of 17 patients improved, and 3 patients remained stable (mean follow-up ; $24.1{\pm}11.2$ months). FVC increased by $20.2{\pm}11.2%$ of predicted value and the extent of ground glass opacity on HRCT decreased significantly ($15.7{\pm}14.7%$). 4) Of the 14 patients who had stopped medication, 5 showed recurrence of NSIP and 2 became aggravated during steroid tapering. All patients with recurrence showed deterioration within one year after completion of initial treatment. Conclusion : Since idiopathic NSIP has unique clinical profiles and shows good prognosis, diagnosis different from UIP, and aggressive medical treatment are needed.

• Explosives and Blasting
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• v.30 no.2
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• pp.29-42
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• 2012

Variables influencing the free face movement due to rock blasting include the physical and mechanical properties, in particular the discontinuity characteristics, explosive type, charge weight, burden, blast-hole spacing, delay time between blast-holes or rows, stemming conditions. These variables also affects the blast vibration, air blast and size of fragmentation. For the design of surface blasting, the priority is given to the safety of nearby buildings. Therefore, blast vibration has to be controlled by analyzing the free face movement at the surface blasting sites and also blasting operation needs to be optimized to improve the fragmentation size. High-speed digital image analysis enables the analyses of the initial movement of free face of rock, stemming optimality, fragment trajectory, face movement direction and velocity as well as the optimal detonator initiation system. Even though The high-speed image analysis technique has been widely used in foreign countries, its applications can hardly be found in Korea. This thesis aims at carrying out a fundamental study for optimizing the blast design and evaluation using the high-speed digital image analysis. A series of experimentation were performed at two large surface blasting sites with the rock type of shale and granite, respectively. Emulsion and ANFO were the explosives used for the study. Based on the digital images analysis, displacement and velocity of the free face were scrutinized along with the analysis fragment size distribution. In addition, AUTODYN, 2-D FEM model, was applied to simulate detonation pressure, detonation velocity, response time for the initiation of the free face movement and face movement shape. The result show that regardless of the rock type, due to the displacement and the movement velocity have the maximum near the center of charged section the free face becomes curved like a bow. Compared with ANFO, the cases with Emulsion result in larger detonation pressure and velocity and faster reaction for the displacement initiation.