• 환경생물
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• 제25권1호
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• pp.27-33
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• 2007

Sediment microcosm experiments were conducted for 14 and 28 days using Zn spiked sediment to examine chronic toxicity (mortality) of Diporeia spp. as a function of density and time. Mean cumulative Diporeia mortality in 28 day sediment microcosms was 25% at $1,800\;{\mu}g\;g^{-1}$ total Zn in sediment. Although a certain fraction $(20{\sim}40%)$ of Diporeia was dead, its mortality was attributed by handling stress within 4 days and was not significantly encreased with increasing within the range of Zn concentrations examined in this study. These results suggest that Diporeia can tolerate Zn contaminated sediment and may be useful as a biomonitor for Zn contamination in freshwater environments.

• Safety and Health at Work
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• 제12권2호
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• pp.174-183
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• 2021

Background: Toluene diisocyanate (TDI) is a highly reactive chemical that causes sensitization and has also been associated with increased lung cancer. A risk assessment was conducted based on occupational epidemiologic estimates for several health outcomes. Methods: Exposure and outcome details were extracted from published studies and a NIOSH Health Hazard Evaluation for new onset asthma, pulmonary function measurements, symptom prevalence, and mortality from lung cancer and respiratory disease. Summary exposure-response estimates were calculated taking into account relative precision and possible survivor selection effects. Attributable incidence of sensitization was estimated as were annual proportional losses of pulmonary function. Excess lifetime risks and benchmark doses were calculated. Results: Respiratory outcomes exhibited strong survivor bias. Asthma/sensitization exposure response decreased with increasing facility-average TDI air concentration as did TDI-associated pulmonary impairment. In a mortality cohort where mean employment duration was less than 1 year, survivor bias pre-empted estimation of lung cancer and respiratory disease exposure response. Conclusion: Controlling for survivor bias and assuming a linear dose-response with facility-average TDI concentrations, excess lifetime risks exceeding one per thousand occurred at about 2 ppt TDI for sensitization and respiratory impairment. Under alternate assumptions regarding stationary and cumulative effects, one per thousand excess risks were estimated at TDI concentrations of 10 - 30 ppt. The unexplained reported excess mortality from lung cancer and other lung diseases, if attributable to TDI or associated emissions, could represent a lifetime risk comparable to that of sensitization.

• Journal of Preventive Medicine and Public Health
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• 제56권1호
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• pp.31-40
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• 2023

Objectives: This study investigated the effect of cognitive impairment on the association between social network properties and mortality among older Korean adults. Methods: This study used data from the Korean Social Life, Health, and Aging Project. It obtained 814 older adults' complete network maps across an entire village in 2011-2012. Participants' deaths until December 31, 2020 were confirmed by cause-of-death statistics. A Cox proportional hazards model was used to assess the risks of poor social network properties (low degree centrality, perceived loneliness, social non-participation, group-level segregation, and lack of support) on mortality according to cognitive impairment. Results: In total, 675 participants (5510.4 person-years) were analyzed, excluding those with missing data and those whose deaths could not be verified. Along with cognitive impairment, all social network properties except loneliness were independently associated with mortality. When stratified by cognitive function, some variables indicating poor social relations had higher risks among older adults with cognitive impairment, with adjusted hazard ratios (HRs) of 2.12 (95% confidence interval [CI], 1.34 to 3.35) for social nonparticipation, 1.58 (95% CI, 0.94 to 2.65) for group-level segregation, and 3.44 (95% CI, 1.55 to 7.60) for lack of support. On the contrary, these effects were not observed among those with normal cognition, with adjusted HRs of 0.73 (95% CI, 0.31 to 1.71), 0.96 (95% CI, 0.42 to 2.21), and 0.95 (95% CI, 0.23 to 3.96), respectively. Conclusions: The effect of social network properties was more critical among the elderly with cognitive impairment. Older adults with poor cognitive function are particularly encouraged to participate in social activities to reduce the risk of mortality.

• 대한기관식도과학회지
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• 제15권2호
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• pp.36-41
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• 2009

Background : Controversy exists whether patients with esophageal carcinoma are best managed with classical Ivor Lewis esophagectomy(ILO) as combined thoracic and abdominal approach or transhiatal esophagectomy(THO). The THO approach is known to be superior with respect to operative time, morbidity and mortality, and length of stay, especially at poor pulmonary function patient, but may represent an inferior cancer operation due to inadequate mediastinal clearance compared with ILO. Accordingly, we estimated the THO role at esophageal cancer to compare each operative approach. Material and Method : From January 2002 to December 2007, we performed a retrospective review of all esophagectomies performed at Keimyung University Dongsan Medical Center; 36 underwent THO, and 11 underwent ILO. Result : There were all men and squamous cell carcinoma but 1 woman at ILO group, 2 women at THO group. There were no significant differences between THO and ILO with age, sex, location of tumor, mean tumor length. There were significant differences at preoperative pulmonary function test(In ILO group, average FEV1 is $2.65{\pm}0.6\;L/min$ and iIn THO group, average FEV1 is $2.07{\pm}0.7\;L/min$). The amount of blood transfusion, hospital stay, leak rates and respiratory complication, hospital mortality rate were not significantly different. Conclusion : There was no significant difference in the post-operative complication, hospital mortality rate, long-term survival of patients of both operative method. THO method had lower mobidity and mortality at poor pulmonary function patient than ILO method. Hence, THO is a valid alternative to ILO for patients with poor general condition or expected post-operative respiratory complication.

• Journal of Chest Surgery
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• 제18권4호
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• pp.605-614
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• 1985

The principal aim of surgery for congenital heart anomalies is the establishment of normal hemodynamic function. Palliative and corrective operations are selected with time to attain this end with minimal risk. In recent years, as operative mortality after primary total correction is lower than the mortality after early palliation and delayed correction, corrective operations in infants have increasingly supplanted palliative ones. Two hundred and eighteen infants below 10 kg with congenital heart anomalies underwent primary surgical intervention at Yonsei Medical Center from March 1979 to June 1985. There were 155 infants with VSD, 35 Infants with TOF, 5 infants with ECD, 4 infants with TGV, 3 infants with DORV, 3 infants with Pulmonary atresia, 3 infants with ASD and PDA, 2 infants with DOLV, and the remainders were Sinus Valsalva rupture, residual mitral regurgitation after total correction of ECD, PAPVR, Cor triatriatum, Truncus arteriosus, and Tricuspid atresia. The overall surgical mortality was 15.1%. In the acyanotic group, 13 infants died among 168 infants, and mortality was 7.7%. But in the cyanotic group, the mortality rate was very high and 20 infants died among 50 infants raising the mortality to 40.0%. These poor surgical results in the cyanotic or complicated group was due to inaccurate diagnosis, improper surgical methods and inadequate post-operative care which should be improved.

• Annals of Clinical Neurophysiology
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• 제25권1호
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• pp.1-9
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• 2023

Breathing is controlled by complex interactions between the central and peripheral nervous systems in conjunction with the respiratory system. Neurological diseases predispose patients to nocturnal desaturation and pneumonia due to respiratory dysfunction, which increases mortality, daytime sleepiness and fatigue, and reduces the quality of life. Respiratory function tests are required to identify respiratory function decline and to consider compensatory management. This review summarizes the characteristics of several respiratory function tests and their applications to neurological diseases.

• Journal of Chest Surgery
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• 제25권11호
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• pp.1218-1220
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• 1992

Pneumonectomy on a patient with documented poor pulmonary function indicating a contraindication to surgery can be associated with a high risk of serious postoperative morbidity or mortality. However the usual criterias, on the performance of a pneumonectomy on a high risk patient based on the preoperative assessment of the pulmonary function may not sometimes predict with accuracy the operative outcome in the postoperative period. We recently performed pneumonectomy with good results on a patient with poor pulmonary function that would otherwise have been an absolute contraindication to surgery by usual criteria.

• Korean Journal of Mathematics
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• 제13권2호
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• pp.161-176
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• 2005

We consider a model of population dynamics whose mortality function is unbounded. We note that the regularity of the solution depends on the growth rate of the mortality near the maximum age. We propose Gauss-Legendre methods along the characteristics to approximate the solution when the solution is smooth enough. It is proven that the scheme is convergent at fourth-order rate in the maximum norm. We also propose discontinuous Galerkin finite element methods to approximate the solution which is not smooth enough. The stability of the method is discussed. Several numerical examples are presented.

• Archives of Pharmacal Research
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• 제7권1호
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• pp.53-56
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• 1984

The effect of twenty two spices on liver microsomal monooxygense activity was tested as measured by alteration of hexobarbital (HB) narcosis and strychnine mortality in mice. Oral administration of seven spices for 7 consecutive days caused a significant shortening of the duration of HB-induced sleeping time. The treatment of mice with a single i. p. injection of 9 spices resulted in a significant prolongation of the sleeping time. White pepper, dill and fennel reduced the toxicity of strychnine. These results strongly indicated that some spices might affect the activity of liver microsomal drug metabolizing enzyme (DME) function.

• 대한수학회논문집
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• 제18권3호
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• pp.569-580
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• 2003

The Lotka-McKendrick equation which describes the evolution of a single population under the phenomenological conditions is developed from the well-known Malthus’model. In this paper, we introduce the Lotka-McKendrick equation for the description of the dynamics of a population. We apply a discontinuous Galerkin finite element method in age-time domain to approximate the solution of the system. We provide some numerical results. It is experimentally shown that, when the mortality function is bounded, the scheme converges at the rate of $h^2$ in the case of piecewise linear polynomial space. It is also shown that the scheme converges at the rate of $h^{3/2}$ when the mortality function is unbounded.