• Tuberculosis and Respiratory Diseases
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• v.73 no.4
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• pp.224-230
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• 2012

Background: We evaluated the clinical outcomes and prognostic factors of patients requiring prolonged mechanical ventilation (PMV), defined as ventilator care for ${\geq}21$ days, who were admitted to the medical intensive care unit (ICU) of a university hospital in Korea. Methods: During the study period, a total of 2,644 patients were admitted to the medical ICU, and 136 patients (5.1%) were enrolled between 2005 and 2010. Results: The mean age of the patients was $61.3{\pm}14.5$ years, and 94 (69.1%) were male. The ICU and six-month cumulative mortality rates were 45.6 and 58.8%, respectively. There were 96 patients with tracheostomy placement after admission and their mean period from admission to the day of tracheostomy was $21.3{\pm}8.4$ days. Sixty-three patients (46.3%) were successfully weaned from ventilator care. Of the ICU survivors (n=74), 34 patients (45.9%) were transferred to other hospitals (not university hospitals). Two variables (thrombocytopenia [hazard ratio (HR), 1.964; 95% confidence interval (CI), 1.225~3.148; p=0.005] and the requirement for vasopressors [HR, 1.822; 95% CI, 1.111~2.986; p=0.017] on day 21) were found to be independent factors of survival on based on the Cox proportional hazard model. Conclusion: We found that patients requiring PMV had high six-month cumulative mortality rates, and that two clinical variables (measured on day 21), thrombocytopenia and requirement for vasopressors, may be associated with prognostic indicators.

• Journal of the Korean Institute of Gas
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• v.20 no.2
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• pp.35-42
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• 2016

Formamide is a colorless fluid with ammonia odor, and irritable when inhaled. It has $LD_{50}$ value of > 5,577 mg/kg in rats for acute oral toxicity and NOAEL of 113 mg/kg/day for target organ (liver) of whole body toxicity. It is also known as reproductive toxicant (1B) and TWA(Time Weighted Average) for it is 10 ppm. Workplace measurements of work places dealing with formamide showed the ppm of all 25 samples was very lower than WEL. However, the exposure concentration can change, depending on workplace condition such as the intensity of work, operating local ventilation system, and wearing protection equipment (Respirators). Therefore, considering it with the risk of whole body toxicity and reproductive toxicity, exposure quantity of each imaginary scenario was calculated at 5.16, 1.72, and $0.43mg/m^3$. The average value was calculated at 0.02-0.58, 0.02-0.66 at 90 percent of cumulative distribution, 0.02-0.69 at 95 percent of cumulative distribution. Therefore, it was generally evaluated to be safe because all values were below 1. However, caution is required to prevent health hazard because it has hepatotoxicity and reproductive toxicity and risk of a high level momentary exposure, depending on the condition of workplace.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.14
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• pp.6111-6116
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• 2015

Background: Stomach cancer is one of leading causes of death worldwide. In Thailand, the incidence and mortality of stomach cancer are in the top ten for cancers. Effects of DNA repair gene X-ray repair cross complementary protein 1 (XRCC1) polymorphisms and clinicopathological characteristics on survival of stomach cancer in Thailand have not been previously reported. The aim of this study was to investigate the effects of XRCC1 gene and clinicopathological characteristics on survival of stomach cancer patients in Thailand. Materials and Methods: Data and blood samples were collected from 101 newly diagnosed stomach cancer cases pathologically confirmed and recruited during 2002 to 2006 and followed-up for vital status until 31 October 2012. Genotype analysis was performed using real-time PCR-HRM. The data were analyzed using the Kaplan-Meier method to yield cumulative survival curve, log-rank test to assess statistical difference of survival and Cox proportional hazard models to estimate adjusted hazard ratio. Results: The total followed-up times were 2,070 person-months, and the mortality rate was 4.3 per 100 person-months. The median survival time after diagnosis was 8.07 months. The cumulative 1-, 3-, 5-years survival rates were 40.4%, 15.2 % and 10.1 % respectively. After adjustment, tumour stage were associated with an increased risk of death (p= 0.036). The XRCC1 Gln339Arg, Arg/Arg homozygote was also associated with increased risk but statistically this was non-significant. Conclusions: In addition to tumour stage, which is an important prognostic factor affecting to the survival of stomach cancer patients, the genetic variant Gln339Arg in XRCC1 may non-significantly contribute to risk of stomach cancer death among Thai people. Larger studies with different populations are need to verify ours findings.

• Journal of Periodontal and Implant Science
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• v.54 no.1
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• pp.53-62
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• 2024

Purpose: This study aimed to evaluate the long-term cumulative survival rate (CSR) of dental implants with micro-threads in the neck over a 10-year follow-up period and to examine the factors influencing the survival rate of dental implants. Methods: This retrospective study was based on radiographic and dental records. In total, 151 patients received 490 Oneplant^® dental implants with an implant neck micro-thread design during 2006-2010 in the Department of Periodontology of Seoul National University Dental Hospital. Implant survival was evaluated using Kaplan-Meier analysis. Cox proportional hazard regression analysis was used to identify the factors influencing implant failure. Results: Ten out of 490 implants (2.04%) failed due to fixture fracture. The CSR of the implants was 97.9%, and no significant difference was observed in the CSR between external-and internal-implant types (98.2% and 97.6%, respectively, P=0.670). In Cox regression analysis, 2-stage surgery significantly increased the risk of implant failure (hazard ratio: 4.769, P=0.039). There were no significant differences in influencing factors, including sex, age, implant diameter, length, fixture type, location, surgical procedure, bone grafting, and restoration type. Conclusions: Within the limitations of this retrospective study, the micro-thread design of the implant neck was found to be favorable for implant survival, with stable clinical outcomes.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.2
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• pp.867-872
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• 2016

Background: Esophageal cancer is one of the most serious malignancies. Due to the aggressive nature of this cancer, the prognosis is poor. A network meta-analysis with simultaneous comparison of multiple treatments can help determine better treatment options that have higher effects on overall survival of patients with lower adverse events. The aim of this review is to simultaneously compare efficacy and adverse events of treatment interventions for esophageal cancer. Materials and Methods: In this review, only randomized control trials (RCT) will be considered for network meta-analysis. All international electronic databases including Medline, Web of Sciences, Scopus, Cochran's library, EMBASE and Cancerlit will be searched to find randomized control trials which compared two or more treatment interventions for esophageal cancer. A network plot will be drawn for visual representation of all available treatment interventions. Bayesian approach will be used to combine the direct and indirect evidence. Treatment effects (e.g. hazard ratio for time to event outcomes, risk ratio for binary outcomes, and rate ratio for count outcomes with 95% credible interval) will be reported. Moreover, cumulative probability of the treatment ranks will be reported using the surface under the cumulative ranking (SUCRA) graphs. Consistency assumption will be assessed by the loop-specific and design-by-treatment interaction approaches. Conclusions: The results of this study may be helpful for the patients, clinicians and health policy makers in selecting treatments that have the best effect on survival and lowest adverse events.

• Journal of Periodontal and Implant Science
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• v.50 no.6
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• pp.379-391
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• 2020

Purpose: The aims of this study were to evaluate the 5-year cumulative survival rate (CSR) of implants placed with guided bone regeneration (GBR) compared to implants placed in native bone, and to identify factors contributing to implant failure in regenerated bone. Methods: This retrospective cohort study included 240 patients who had implant placement either with a GBR procedure (regenerated bone group) or with pristine bone (native bone group). Data on demographic features (age, sex, smoking, and medical history), location of the implant, implant-specific features, and grafting procedures and materials were collected. The 5-year CSRs in both groups were estimated using Kaplan-Meier analysis. Risk factors for implant failure were analyzed with a Cox proportional hazards model. Results: In total, 264 implants in the native bone group and 133 implants in the regenerated bone group were analyzed. The 5-year CSRs were 96.4% in the regenerated bone group and 97.5% in the native bone group, which was not a significant difference. The multivariable analysis confirmed that bone status was not an independent risk factor for implant failure. However, smoking significantly increased the failure rate (hazard ratio, 10.7; P=0.002). Conclusions: The 5-year CSR of implants placed in regenerated bone using GBR was comparable to that of implants placed in native bone. Smoking significantly increased the risk of implant failure in both groups.

• Journal of Periodontal and Implant Science
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• v.53 no.6
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• pp.444-452
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• 2023

Purpose: The aim of this study was to retrospectively evaluate the survival and failure rates of RESTORE^® implants over a follow-up period of 10-15 years at a university dental hospital and to investigate the factors affecting the survival rate of these dental implants. Methods: A total of 247 RESTORE^® dental implants with a resorbable blast media (RBM) surface inserted in 86 patients between March 2006 and April 2011 at the Department of Periodontology of Seoul National University Dental Hospital were included. Patients with follow-up periods of less than 10 years were excluded, and data analysis was conducted based on dental records and radiographs. Results: Over a 10- to 15-year period, the cumulative survival rate of the implants was 92.5%. Seventeen implants (6.88%) were explanted due to implant fracture (n=10, 4.05%), peri-implantitis (n=6, 2.43%), and screw fracture (n=1, 0.4%). The results of univariate regression analysis using a Cox proportional hazards model demonstrated that implants placed in male patients (hazard ratio [HR], 4.542; 95% confidence interval [CI], 1.305-15.807; P=0.017) and implants that supported removable prostheses (HR, 15.498; 95% CI, 3.105-77.357; P=0.001) showed statistically significant associations with implant failure. Conclusions: Within the limitations of this retrospective study, the RESTORE^® dental implant with an RBM surface has a favorable survival rate with stable clinical outcomes.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.4
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• pp.99-106
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• 2009

This research was to estimate quantitative infiltration volume of permeable block which is one of runoff reduction infiltration facilities. In this research, the permeable block experiments estimating infiltration volume for 50, 100, 150, 200 mm/hr rainfall intensity were carried out and hydraulic experiments results were compared with numerical simulation output to produce feasibility of numerical simulation. Final infiltration capacity analysis of permeable block hydraulic experiments reveals that every estimated infiltration volume before runoff beginning was above approximately 300.0 l despite rapid reduction of infiltration ratio and runoff initiation time were occurred in every rainfall intensity. Statistical calculation for coefficient of determination based on cumulative infiltration volume of hydraulic experiment and numerical simulation resulted in a high correlationship as $0.958{\sim}0.996$.

• Journal of the Korean Society of Hazard Mitigation
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• v.6 no.3 s.22
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• pp.57-68
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• 2006

The objective of this study is to analyze the temporal pattern characteristic of short-duration rainfall defined as a rainfall durations of 6 hours or less by the Huff's 4th quartile distribution. To analyze the temporal pattern characteristic of short-duration rainfall, the rainfall data are classified by rainfall duration and rainfall type(Changma, Typhoon, Severe rain storm, Frontal storm) and change of rainfall segment. Also, the results of this study compared with result of research work of Korea Institute of Construction Technology(1989) and Ministry of Construction & Transportation(2000). The conclusions of this study are as follows; (1) Short-duration rainfall with duration of 6 hours or less is found to be most prevalent frist-quartile storms. (2) In the case of rainfall type, Changma and Severe rain storms and Frontal storm is found second-quartile storms, and Typhoon is found third-quartile storms. (3) In the result by change of sixth segment storms, the type of temporal pattern of rainfall is found to be most prevalent two sixth parts, (4) Comparative analysis of the results shows that shapes of the dimensionless cumulative curves and values are different from those of existing researches.

• Journal of Periodontal and Implant Science
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• v.49 no.5
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• pp.287-298
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• 2019

Purpose: The aim of this retrospective study was to determine the prevalence of early implant failure using a single implant system and to identify the factors contributing to early implant failure. Methods: Patients who received implant treatment with a single implant system ($Luna^{(R)}$, Shinhung, Seoul, Korea) at Dankook University Dental Hospital from 2015 to 2017 were enrolled. The following data were collected for analysis: sex and age of the patient, seniority of the surgeon, diameter and length of the implant, position in the dental arch, access approach for sinus-floor elevation, and type of guided bone regeneration (GBR) procedure. The effect of each predictor was evaluated using the crude hazard ratio and the adjusted hazard ratio (aHR) in univariate and multivariate Cox regression analyses, respectively. Results: This study analyzed 1,031 implants in 409 patients, who comprised 169 females and 240 males with a median age of 54 years (interquartile range [IQR], 47-61 years) and were followed up for a median of 7.2 months (IQR, 5.6-9.9 months) after implant placement. Thirty-five implants were removed prior to final prosthesis delivery, and the cumulative survival rate in the early phase at the implant level was 95.6%. Multivariate regression analysis revealed that seniority of the surgeon (residents: aHR=2.86; 95% confidence interval [CI], 1.37-5.94) and the jaw in which the implant was placed (mandible: aHR=2.31; 95% CI, 1.12-4.76) exerted statistically significant effects on early implant failure after adjusting for sex, age, dimensions of the implant, and type of GBR procedure (preoperative and/or simultaneous) (P<0.05). Conclusions: Prospective studies are warranted to further elucidate the factors contributing to early implant failure. In the meantime, surgeons should receive appropriate training and carefully select the bone bed in order to minimize the risk of early implant failure.