• 한국산학기술학회논문지
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• 제8권1호
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• pp.130-135
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• 2007

국내 수질의 부식성을 파악하기 위해 RTW 모델과 LPLWIN 모델을 이용하여 탄산칼슘포화지수를 포함한 다양한 지수를 산정하는 절차를 연구하였다. RTW 모델을 이용하여 LI, RI, AI 를 산정할 수 있었고, LPLWIN 모델을 이용하여 LI, LR, CCPP를 산정하였다. 한강 수계와 낙동강 수계를 취수원으로 하는 수돗물 자료를 적용하여 지수값에 근거하여 부식성 여부를 판단하였다. 산정결과에 의하면, 낙동강 수계는 한강수계보다 부식성이 양호한 수질인 것으로 나타났다. 겨울철이 여름철에 비하여 부식성이 큰 것으로 나타나, 온도가 증가할수록 부식성은 감소하는 것으로 조사되었다.

• Journal of Nutrition and Health
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• 제26권6호
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• pp.692-702
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• 1993

To evaluate iron nutritional status and to compare biochemical indices used for evaluation of iron nutriture, fasting blood sample was taken from 96 Korean female college student and hemoglobin(Hb) concentration, hematocrit(Hct), serum iron, total iron binding capacity(TIBC) and serum ferritin concentration were measured and transferrin(TF) saturation was calculated. Prevalence of iron deficiency varied from 4.2% when judged from Hb concentration and Hct to 38.5% and 40.6% when TIBC and serum ferritin concentration were used. TIBC was negatively correlated with serum ferritin(r=0.4561, p<0.001), while other indices showed positive but less significant correlations(p<0.05). Regarding iron status judged by serum ferritin was regarded as true iron status, the present cutoff points of Hb, Hct, serum iron, TF saturation were very insensitive in identifying the subjects with iron deficiency. Only TIBC was suitable for detecting iron deficiency in the study subjects. It is concluded from the study results that iron deficiency in young Korean adult women would be significantly underestimated with presently used biochemical measurements except TIBC and new cutoff points of these indices were proposed based on sensitivity, specificity measured prevalence, and positive and negative predictive values.

• Korean Journal of Radiology
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• 제22권5호
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• pp.770-781
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• 2021

Objective: Chemical exchange-dependent saturation transfer (CEST) MRI is sensitive for detecting solid-like proteins and may detect changes in the levels of mobile proteins and peptides in tissues. The objective of this study was to evaluate the characteristics of chemical exchange proton pools using the CEST MRI technique in patients with dementia. Materials and Methods: Our institutional review board approved this cross-sectional prospective study and informed consent was obtained from all participants. This study included 41 subjects (19 with dementia and 22 without dementia). Complete CEST data of the brain were obtained using a three-dimensional gradient and spin-echo sequence to map CEST indices, such as amide, amine, hydroxyl, and magnetization transfer ratio asymmetry (MTR_asym) values, using six-pool Lorentzian fitting. Statistical analyses of CEST indices were performed to evaluate group comparisons, their correlations with gray matter volume (GMV) and Mini-Mental State Examination (MMSE) scores, and receiver operating characteristic (ROC) curves. Results: Amine signals (0.029 for non-dementia, 0.046 for dementia, p = 0.011 at hippocampus) and MTR_asym values at 3 ppm (0.748 for non-dementia, 1.138 for dementia, p = 0.022 at hippocampus), and 3.5 ppm (0.463 for non-dementia, 0.875 for dementia, p = 0.029 at hippocampus) were significantly higher in the dementia group than in the non-dementia group. Most CEST indices were not significantly correlated with GMV; however, except amide, most indices were significantly correlated with the MMSE scores. The classification power of most CEST indices was lower than that of GMV but adding one of the CEST indices in GMV improved the classification between the subject groups. The largest improvement was seen in the MTR_asym values at 2 ppm in the anterior cingulate (area under the ROC curve = 0.981), with a sensitivity of 100 and a specificity of 90.91. Conclusion: CEST MRI potentially allows noninvasive image alterations in the Alzheimer's disease brain without injecting isotopes for monitoring different disease states and may provide a new imaging biomarker in the future.

• 대한의용생체공학회:의공학회지
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• 제15권3호
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• pp.265-274
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• 1994

This paper proposes a method of noninvasive reflectance light to measure the blood fractional volume (Vb) and oxygen saturation ($SO_2$) of biological tissue. We chose the red light of 660nm and infrared light of 880nm. In Vivo reflectance data were obtained by the physiological changes front the surface of the skin over the calf in human subject. The reflected light intensity from different layers within a biological tissue was measured by specially designed reflectometer to apply photon path diffusion model. The collected data represent the changes of blood (ractional volume and oxygen saturation at each reflected light wavelengths. The data evaluation was assessed by examining the slopes of the plotted indices for the changes in oxygen saturation and blood (ractional volume. The results presented in this paper claim that light reflectance can separately discriminate the change of blood volume and that of oxygenation in muscle and also in skin.

• Journal of Chest Surgery
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• 제25권11호
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• pp.1192-1202
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• 1992

Postoperative cardiac outputs and other hernoaynamic values were serially measured in fifteen patients of cyanotic congenital heart disease, after use of blood cardioplegic solution. Cardiac indices showed no change untill eight postoparative hours, then it began to decline to reach as low as 3.22$\pm$0.7L/min/m2 at 12 hours. After then gradual increse occ-ured to recover upto immediate postoperative value at 20 hours. Sharp decrese of heart rate and increse of systemic vascular resistance during 8~16 hours and steady increase of stroke indices during the whole study periods were observed. These observations suggested that the myocardium recovered gradually after open heart surgery, and that the decrease of cardiac indices during 8~16 hours could be a result of decrease of heart rates and increase of afterload. The changes of cardiac indices correlated with the changes of heart rate, postoperative time and mixed venous oxygen saturation [p<0.05]. No other hemodynamic values found to be in statistically significant correlation with the changes of cardiac indices. Left ventricular dysfunction seemed to occur more frequently during 8~12 hours, but it was not statistically significant. [p=0.73] In conclusion, great care must be taken during 2~3 days after the operation of cyanotic congenital heart disease, not to fall into a low cardiac output state, by maintaing adequate heart rates and reducing afterload especially when the systemic vascular resistance increases.

• 상하수도학회지
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• 제32권2호
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• pp.183-192
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• 2018

Applicability of corrosion inhibitor was evaluated using pilot scale water distribution pipe simulator. Calcium hydroxide was used as corrosion inhibitor and the corrosion indices of the water were investigated. Corrosion indices, Langelier saturation index (LI) increased by 0.8 and calcium carbonate precipitation potential (CCPP) increased by 9.8 mg/L. This indicated that corrosivity of water decreased by corrosion inhibitor and the effects lasted for 18 days. Optimum calcium hydroxide dose was found to be 3~5 mg/L for corrosion inhibition. We suggest that monitoring of CCPP as well as LI need to be conducted to control corrosivity of water.

• 한국산업보건학회지
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• 제34권1호
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• pp.57-66
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• 2024

Objective: Chronic obstructive pulmonary disease (COPD) is characterized by progressive airflow obstruction that is only partly reversible, inflammation in the airways, and systemic effects. This study aimed to investigate the association between low peripheral oxygen saturation levels (SpO₂), and composite indices predicting death in male patients with (COPD). Method: A total of 140 participants with post-bronchodilator FEV₁/FVC ratio less than 0.7 were included. Three composite indices (ADO, DOSE, BODEx) were calculated using six variables such as age (A), airflow obstruction (O), body mass index (B), dyspnea (D), exacerbation history (E or Ex), and smoking status (S). Severity of airflow limitation was classified according to Global Initiative for Obstructive Lung Disease (GOLD) guidelines. SpO₂ was measured by pulse oximetry, and anemia and iron deficiency were assessed based on blood hemoglobin levels and serum markers such as ferritin, transferrin saturation, or soluble transferrin receptor. Results: Participants with low SpO₂ (<95%) showed significantly lower levels of %FEV₁ predicted (p=0.020) and %FEV₁/FVC ratio (p=0.002) compared to those with normal SpO₂ levels. The mMRC dyspnea scale (p<0.001) and GOLD grade (p=0.002) showed a significant increase in the low SpO₂ group. Receiver Operating Characteristic analysis revealed higher area under the curve for %FEV₁ (p=0.020), %FEV₁/FVC(p=0.002), mMRC dyspnea scale (p=0.001), GOLD grade (p=0.010), ADO (p=0.004), DOSE (p=0.002), and BODEx (p=0.011) in the low SpO₂ group. Conclusion: These results suggest that low SpO₂ levels are related to increased airflow limitation and the composite indices of COPD.

• 대한임상검사과학회지
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• 제43권4호
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• pp.188-193
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• 2011

Obstructive sleep apnea (OSA) is the most common type of sleep apnea and is caused by obstruction of the upper airway. Since it is closely related to sleep parameter and body indices, the study was focused on the relationship with them. The results of polysomnography (PSG) in obstructive sleep apnea was done at ENT department of Ewha women university Mokdong hospital from March to September 2010 with 52 subjects (male 35, female 17). The leads were placed to measure electroencephalogram (EEG), electrooculogram (EOG), mandibular and anterior tibialis electromyogram (EMG), airflow in nasal and oral cavity, chest and abdominal breathing pattern, snoring sound and arterial oxygen saturation ($SpO_2$) level. From sleep parameter and body indices of adult obstructive sleep apnea compared to normal adult revealed that age (p<0.01) and snoring sound (p<0.05) were increased, stage 1 sleep (p<0.01) was increased, the deeper stages (3&4) of sleep (p<0.05) were reduced. Respiratory disturbance index (RDI) (p<0.01), mean $SpO_2$ (p<0.05) and lowest $SpO_2$ (p<0.01) were also decreased. The correlation analysis from sleep parameter and body indices of OSA showed the positive correlation with age (r=0.463, p<0.001), snoring sound (r=0.278, p<0.05), stage 1 sleep (r=0.391, p<0.01) and RDI (r=0.409, p<0.01), but showed the negative correlation with the deeper stages (3&4) of sleep (r=-0.307, p<0.05), mean $SpO_2$=(r=-0.274, p<0.05) and lowest $SpO_2$ (r=-0.392, p<0.01). This study proves that obstructive sleep apnea and indices have closed related.

• 상하수도학회지
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• 제11권1호
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• pp.53-63
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• 1997

The corrosion problems in water distribution system are reduced by decreasing the agressivity of drinking water which is evaluated by marble test and saturation indices(LSI or CCPP etc.). Marble test is a reliable method to determine the actual saturation condition of treated water. This study was done to determined the aggressivity of tap water and the effectiveness of $Ca(OH)_2$ and NaOH dosage for corrosion control. The drinking water in Seoul were evaluated by marble test and Langelier Index(LSI) and Calcium Carbonate Precipitation Potential(CCPP). The results indicated that the drinking water in Seoul were undersaturated as Calcium Carbonate($CaCO_3$). The LSI and CCPP of the water treated with $Ca(OH)_2$ were higher than that of water treated with NaOH. Therefore, to increase the Alkalinity and Calcium Hardness for corrosion control in water distribution system, $Ca(OH)_2$ is more effective than NaOH.

• Journal of Korean Biological Nursing Science
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• 제2권1호
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• pp.76-84
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• 2000

Recently, music therapy is widely used for various kinds of diseases. Music therapy has beneficial effects on emotional disorder and neuropsychiatric diseases in particular. This study was performed to evaluate the effect of singing on physiologic changes. We checked peripheral oxygen saturation and heart rate as indices of physiologic changes. The subjects were 19 control and 30 test group who were registered on the D welfare center for the elderly and agreed to join this study. They had been singing regularly for 6 months. The data were collected just before and after the singing. Data were analyzed with mean, t-test, and paired t-test using SPSS $PC^+$ program. The results were as follows: 1. Heart rate of the singing group decreased significantly after singing.(p<0.05) 2. Peripheral oxygen saturation of the singing group increased significantly after singing.(p<0.05) In conclusion, singing, a kind of aerobic exercise, has beneficial effects on cardiopulmonary system.