Nutrienr cyclings in mongolian oak(quercus mongolica) forest

Kwak, Young-Se,Kim, Joon-Ho The Ecological Society of Korea 1992 Journal of Ecology and Environment Vol.15 No.1

To elucidate nutrient cyclings such as nitrogen, phosphorus and potassium in mongolian oak(quercus mongolica) forest, nutrient elements of precipitation, throughfall, outflow, soil, various plant organ and litter were determined at mt.nambyeongsan, pyeongchang-gun, gangwon province in central part of korean peninsula. Annual precipitation input, throughfall and outflow of nutrientswere 10.3, 8.6 and 4.2 kg/ha for the N, 0.11, 0.24 and 0.02 kg/ha for the Pand 1.3, 10.9 and 1.2 kg/ha for the K, respectively. Inseasonal changes of nutrient concentrations, N, P and Kconcentrations which were rich in young leaves decreased steadily until autumn and decreased abruptly during autumnal yellowing. The standing N, P and K concent were 565, 37 and 257 kg/ha for standing phytomass of overstory, 33, 3 and 18 kg/ha for understory, 132, 3.6 and 14 kg/ha for litter on ground including deadwood and 20, 752, 14 and 420 kg/ha for the soil, respectively. The amounts of annual uptake, reture and retain were 174.2, 57.2, 117.2 kg/ha for the N, 9.9, 3.5, 6.4 kg/ha for the P and 73.2, 30.3, 42.9 kg/ha for the K, respectively. Reabsorption efficiency, ratio of the nutrient amount reabsorbed into woody organs to that in the mature leaves before shedding, was 71%(or 99.8 kg/ha in the amount), 69%(or 5.1 kg/ha) and 57%(or 33.1% kg/ha) and recycling coeffciently made with which the large amount of nutrients is absorbed through roots during growing season(UPTAKE) and reasorbed from the leaves before shedding(RETAIN) but the small amount of nutrients is returned through litterfall(RETURN).

Comparison of the Structure of Grassland Communities and the Performance of Galcicoles and Calcifuges on the Limiestone and the Granite Areas

Kwak, Young-Se,Chin, Kuk-Jeong,Min, Kuem-Suk,Kim, Joon-Ho,Choung, Yeon-Sook The Ecological Society of Korea 1994 Journal of Ecology and Environment Vol.17 No.2

Structure of grassland communities was investigated, and performance of populations of Themeda triandra var. japonica and Miscanthus sinensis were compared on limestone and granite soils. Forty three and forty taxa occurred on the limestone and granite grasslands, respectively, but their similarity was very low. Shoot height and number of hills per patch, as a measure of performance, of Themeda on the limestone grassland were higherthan those on the granite grassland. In contrast, shoot height and number on hills per patch of Miscanthus were higher on limestone than granite grassland. Evidence shows that poor growth of Micanthus population on the limestone soil was associated with higher content of insoluble divalent cations than soluble ones in shoot tissue.

Treatment outcomes of patients with isoniazid mono-resistant tuberculosis

( Se Hyun Kwak ),( Joon Chang ),( Young Sam Kim ),( Moo Suk Park ),( Ji Ye Jung ),( Kyung Soo Chung ),( Song Yee Kim ),( Sang Hoon Lee ),( Su Hwan Lee ),( Ah Young Leem ),( Eunhye Lee ),( Ji Soo Choi 대한결핵 및 호흡기학회 2019 대한결핵 및 호흡기학회 추계학술대회 초록집 Vol.127 No.-

Background: Confirmed rifampicin susceptible and isoniazid (INH) resistant tuberculosis is the most common type of first line drug resistant tuberculosis (TB). However, the most recommended therapeutic regimens and duration of treatment for INH mono resistant TB have not been well established. Methods: We retrospectively reviewed for cases of culture confirmed INH mono-resistant TB reported to one tertiary care hospital in South Korea from 2005.1.1 to 2018.12.31. Among them, we excluded the patients with resistance to INH and one other first line anti-TB drug, those who have already started treatment at another hospital, those who were not prescribed medication at our hospital, and those who are currently under treatment. Results: The medical records of 266 patients with INH-resistant TB were evaluated. Among them, 195 patients met the inclusion criteria. According to the current World Health Organization (WHO) guidelines, 165 (84.6%) had treatment success, including cure and treatment completion. However, unfavorable outcomes occurred in 8 patients (4.1%), including treatment failure (n=3, 1.5%) and relapse after initial treatment completion (n=5, 2.6%). Overall, a total of 160 patients (82.1%) had favorable outcomes, who completed/cured without relapse. Compared with patients with favorable outcomes, those with unfavorable outcomes were more likely to have chronic kidney disease (CKD) (p=0.003), more likely to have positive baseline positive AFB smear (p=0.006) and positive AFB culture at 1 month of treatment (p=0.028). Two variables (Chronic kidney disease and baseline positive AFB smear) were significantly associated with increased risk of unfavorable outcomes in a multivariable analysis. (OR=10.104, 95% CI 1.375-39.378, and OR 7.357, 95% CI 1.374-39.378, respectively). Conclusions: Our data suggest that underlying CKD and positive AFB smear are probably associated with unfavorable outcomes of INH-resistant TB.

Identification of Biomarkers of Sepsis-associated Acute Kidney Injury Using Metabolomics Amino Acids Profiling in Intensive Care Unit

( Se Hyun Kwak ),( Sunyoung Ahn ),( Seung Hyun Yong ),( Ah Young Leem ),( Su Hwan Lee ),( Sang Hoon Lee ),( Song Yee Kim ),( Kyung Soo Chung ),( Eun Young Kim ),( Ji Ye Jung ),( Young Ae Kang ),( Youn 대한결핵 및 호흡기학회 2020 대한결핵 및 호흡기학회 추계학술대회 초록집 Vol.128 No.-

Background Acute kidney injury (AKI) following sepsis has been known to be associated with increased mortality. Methods Sepsis or septic shock patients admitted to medical ICU were enrolled from June 2018 through May 2019 at Severance hospital. End stage renal disease patients on dialysis were excluded. We divided septic patients into those with and without AKI within 48hr after admission to the ICU (D0). Patients with septic AKI were subdivided into AKI recovery and non-recovery groups according to whether kidney injury recovered within 7 days of the initiating event. We collected the serum samples of patients on D0. We used liquid chromatography tandem mass spectrometry (LC-MS/MS) for the application of metabolomics to research, and analyzed the Results to evaluate potential biomarkers of septic AKI. Results Of the 91 patients, 42 had sepsis, and 49 had septic shock. 84 were included with a median age of 71.0 (IQR 60.9-80.2). Compared with non-AKI and recovery AKI group, non-recovery AKI group showed highest baseline creatine (2.9 vs 1.2 vs 0.8, p<0.001), CCI (4.5 vs 3.0 vs 2.0, p=0.002), SOFA (10.0 vs 8.0 vs 6.5, p<0.001), and APACHE II score (32.0 vs 30.5 vs 21.5, p=0.004). In-hospital (73.3% vs 15.0% vs 23.5%, p<0.001) and 90-day mortality (66.7% vs 20.0% vs 20.6%, p<0.001) were also highest in the non-recovery AKI group. As a result of metabolomics approach using LC-MS/MS, hydroxyproline (14.7 vs 11.3, p≤0.01) and kynurenine (6.6 vs 3.3, p≤0.01) concentration at D0 in non-recovery AKI group were significantly lower than in that in those in non-AKI group. The area under the curve for hydroxyproline and kynurenine for prediction of non-recovery AKI were 0.646 (95% CI 0.517-0.762) and 0.740 (95% CI 0.615-0.842), respectively. Conclusions Our Results suggest that hydroxyproline and kynurenine could be useful biomarkers for non-recovery AKI diagnosis in sepsis patients in ICU.

Clinical Outcome of Patients that Underwent Tracheostomy in Medical Intensive Care Unit

( Se Hyun Kwak ),( Nam Eun Kim ),( Youngmok Park ),( Seung Hyun Yong ),( Ah Young Leem ),( Sang Hoon Lee ),( Song Yee Kim ),( Kyung Soo Chung ),( Eun Young Kim ),( Ji Ye Jung ),( Young Ae Kang ),( Moo 대한결핵 및 호흡기학회 2020 대한결핵 및 호흡기학회 추계학술대회 초록집 Vol.128 No.-

Background We evaluated survival after tracheostomy and identified potential variables predicting weaning outcome in patients who underwent tracheostomy. Methods We retrospectively reviewed the medical records of patients that underwent tracheostomy in medical intensive care unit (ICU) of a tertiary referral hospital in South Korea between July 11, 2016 and April 10, 2019. We excluded patients who underwent tracheostomy before ICU admission and those who failed discontinuation of mechanical ventilation. The primary outcome was weaning failure, defined as prolonged home ventilator support. Tracheostomy tube de-cannulation or sealing off were considered a successful weaning, Results 271 patients received tracheostomy, and a total of 182 patients were included with a median age of 68.2 (IQR 57.5-77.0) years and median APACHE II score of 26.0 (IQR 20.5-31.0). The most common indication for tracheostomy was pulmonary problems (74.7%), followed by neurologic (8.8%), cardiac (3.3%), and neuromuscular (1.1%) problems. The median ICU length of stay was 89.5 (IQR 56.5-150.3) days and overall in-hospital mortality was 19.2%. Of the 182 patients, 113 (62.1%) experienced successful weaning, otherwise 69 (37.9%) patients failed to wean. There was statistically significant longer survival in weaning success group to weaning failure group (p<0.001). Multivariated analysis showed that potential factors associated with weaning failure were past history of coronary artery occlusive disease (CAOD, odds ratio [OR], 3.045; 95% confidence interval [CI], 1.237 to 7.494; p=0.015) and congestive heart failure (CHF, OR, 3.464; 95% CI, 1.171 to 10.246; p=0.025). Conclusions In our ICU, 62.1% of patients who received tracheostomy were successfully weaned. The most common reason of tracheostomy was pulmonary problems. In addition, CAOD and CHF could be predictive of weaning failure in ICU patients who underwent tracheostomy.

Characteristics and risk factors associated with missed diagnosis in patients with smear-negative pulmonary tuberculosis

( Se Hyun Kwak ),( Ji Soo Choi ),( Eun Hye Lee ),( Su Hwan Lee ),( Ah Young Leem ),( Sang Hoon Lee ),( Song Yee Kim ),( Kyung Soo Chung ),( Ji Ye Jung ),( Moo Suk Park ),( Young Sam Kim ),( Joon Chang 대한내과학회 2021 The Korean Journal of Internal Medicine Vol.36 No.0

Background/Aims: Delayed diagnosis and treatment of smear-negative pulmonary tuberculosis (TB) are major concerns for TB control. We evaluated characteristics of patients with smear-negative pulmonary TB who received a delayed diagnosis and identified risk factors that may have contributed to this delay. Methods: We reviewed medical records of patients with smear-negative culture-positive pulmonary TB treated at a tertiary care hospital in South Korea between January 2017 and December 2018. Patients who initiated anti-TB treatment after positive cultures were included in the missed TB group, and those who initiated empirical treatment before positive cultures were included in the control group. Results: Of 220 patients included, 117 (53.2%) and 103 (46.8%) were in the missed TB and control groups, respectively. Patients in the missed TB group were older (p = 0.001) and had a higher mean body mass index (BMI) (p = 0.019). Comorbidities (66.9% vs. 46.6%, p = 0.003) and immunocompromised patients (33.1% vs. 20.4%, p = 0.035) were more common in the missed TB group than in the control group. Old age (odds ratio [OR], 1.030; 95% confidence interval [CI], 1.012 to 1.048; p = 0.001), high BMI (OR, 1.114; 95% CI, 1.004 to 1.237; p = 0.042), and negative polymerase chain reaction (PCR) results (OR, 9.551; 95% CI, 4.925 to 18.521; p < 0.001) were associated with delayed diagnosis. Conclusions: In more than half of patients with smear-negative pulmonary TB, the diagnosis was delayed. Patients with delayed TB diagnosis were older, had higher BMI, and negative PCR results.

Community Structure, Phytomass, and Primary Productivity in Thuja orientalis Stands on Limestone Area

Kwak, Young-Se,Lee, Choong-Il The Korean Environmental Sciences Society 1999 Environmental sciences Vol.3 No.3

The community structure, phytomass, and primary productivity in Thuja orientalis stands on a limestone area located in Maepo-up, Chungbuk province in Korea were estimated quantitatively. Seven species including a small proportion of Quercus dentata were identified in the tree layer, 26 species including Ulmus macrocarpa in the shrub layer, and 79 species including Carex lnceolata in the herb layer of the Thuja stands. The vertical distribution of the fine root phytomass exhibited a power functional decrease relative to the soil depth. The seasonal changes in the fine root phytomass at a soil depth of 5 cm were closely related to the pecipitation in the study area. The productivity of the stand of stems, branches, leaves, and roots were 10.72, 0.82, 0.45 and 6.46 ton DM. $ha^{-1}$ .$yr^{-1}$, respectively. The Thuja stand had a high foliage(25%) and low rate of production per unit of foliage. The annual turnover rate of the fine roots int he Thuja stand was 6.71 $yr^{-1}$. The net primary production of the overstory including the understory was estimated at 19.48 ton DM.$ha^{-1}$.$yr^{-1}$ including an underground section of 6.46 ton DM.$ha^{-1}$.$yr^{-1}$(33%). The allocation ratio of net production to root was lower in the limestone Thuja communities than at the nearby non-limestone ones, whereas the production efficiency to leaf weight was higher in the limestone communities. These results would seem to indicate that the limited production capacity is due to the calcium toxicity and low availability of iron and phosphorus in a limestone soil with a high pH, calcium, and bicarbonate content with a strategy for survival in a hostile habitat.

Development and Roll-Out of A Coronavirus Disease 2019 Clinical Pathway for Standardized Qualified Care in Public Hospitals in Korea

Kwak Mi Young,Jo Eun Young,Chin Bum Sik,Park Se Eun,Yim Jun,Lee Jung Eun,Jo Kyung Eun,Kim Yeon-Sook,Lee Jeong Eun,Yoon Young Kyung,Seo Yu Bin,Jeong Su Jin,Kang Yu Min,Joo Eun-Jeong,Yoon Jong Hyun,Kim 대한감염학회 2022 Infection and Chemotherapy Vol.54 No.2

Despite the coronavirus disease 2019 (COVID-19) vaccination roll-out, variant-related outbreaks have occurred repeatedly in Korea. Although public hospitals played a major role in COVID-19 patients’ care, difficulty incorporating evolving COVID-19 treatment guidelines called for a clinical pathway (CP). Eighteen public hospitals volunteered, and a professional review board was created. CPs were formulated containing inclusion/exclusion criteria, application flow charts, and standardized order sets. After CP roll-out, key parameters improved, such as increased patient/staff five-point satisfaction scores (0.41/0.57) and decreased hospital stays (1.78 days)/medical expenses (17.5%). The CPs were updated consistently after roll-out as new therapeutics drugs were introduced and quarantine policies changed.

Three Month Follow-up Study of the Pulmonary Function among Severe COVID-19 Pneumonia Survivors

( Se Hyun Kwak ),( Min Chul Kim ),( Ji Soo Choi ),( Chang Hwan Seol ),( Sung-ryeol Kim ),( Eun Hye Lee ),( Byung Hoon Park ),( Ah Young Leem ),( Kyungsoo Chung ),( Moo Suk Park ),( Young Sam Kim ),( S 대한결핵 및 호흡기학회 2021 대한결핵 및 호흡기학회 추계학술대회 초록집 Vol.129 No.0

Background Though coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus-2 affects multiple organs, especially the respiratory system, the pulmonary sequelae in patients surviving severe COVID-19 pneumonia remains unclear. Therefore, we aimed to evaluate mid-term clinical effects of COVID-19 pneumonia on lung function in COVID-19 survivors. Methods Patients who survived from COVID-19 pneumonia were included and evaluated three months after discharge at a South Korean tertiary referral hospital from July 2020 to August 2021. Non-recovered patients who were unable to perform the pulmonary function test measurements were excluded. Participants were divided into two groups according to the severity of pneumonia: A non-severe COVID-19 group that did not require mechanical ventilation, and a severe COVID-19 group receiving mechanical ventilation in intensive care unit. Results Of 58 survivors included, 44 (75.9%) and 14 (24.1%) were in the non-severe COVID-19 and severe COVID-19 groups, respectively. 23 (39.7%) were male, and the median age was 68.0 [interquartile range, 59.5-73.5] years. There were no statistically significant differences between the two groups in pulmonary function test data including forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), forced expiratory flow at 25-75% of FVC, FEV1/FVC, and diffusing capacity at the three months follow-up. Conclusions Even in patients with respiratory failure due to severe or critical COVID-19 pneumonia, there was no significant impairment of lung function after three months of recovery compared to patients with non-severe COVID-19 pneumonia. Further studies are needed on long-term follow-up of the lung function in COVID-19 pneumonia.

Spatial Distribution of Fine Roots in Quercus mongolica and Quercus acutissima Stands

Kwak, Young-Se,Kim, Joon-Ho The Ecological Society of Korea 1994 Journal of Ecology and Environment Vol.17 No.2

Vertical and horizontal distribution and seasonal changes of fine roots as well as inorganic nitrogen content in soil were determined in Quercus mongolica and Quercus acutissima stands in Mt. Taemosan, Seoul. The vertical distribution of fine rooth phytomass showed a power-functional decrease as descending soil depth. Fine root phytomass was 170 g $DM/m^2$(46%) and 225 g $DM/m^2$(47%) in top soil of 5 cm depth, and 370 g $DM/m^2$ and 480 g $DM/m^2$ from soil surface to 50 cm depth in Q. mongolica and Q. acutissima stands, respectively. Fine roots in relation to the distance from the nearest tree were evenly distributed horizontally in both stands. Fine roots phytomass in top soil of 5 cm depth reached a peak in June, and thereafter decreased gradually in both stands. Patterns of seasonal changes in fine root phytomass were closely related to inorganic nitrogen and moisture content.