• Journal of the Korean Society of Hazard Mitigation
• /
• v.11 no.3
• /
• pp.237-243
• /
• 2011

As the effluent quality standard of the municipal wastewater treatment plant (MWTP) has been strengthened, the treatment of the recycle water containing high concentration of ammonium nitrogen has been considered as one of retrofit methods for upgrading the exising MWTPs. In this study, nitritation, economic nitrogen removal process, was induced by laboratory-scale reactor at the $35^{\circ}C$, $20^{\circ}C$, and $10^{\circ}C$ temperature conditions using anaerobic digester supernatant. The stable nitritation was achieved over $20^{\circ}C$, but nitrification was induced at $10^{\circ}C$. It means that the nitritation was affected by SRT and temperature. SRT, demanded for nitritation, is changed according to the temperature. Therefore, it is considered that SRT and temperature are important factors in nitritation. Also, it is approved that inducing the ammonium nitrogen removal and the nitritation are more beneficial over $20^{\circ}C$. The conclusion of this study can be used for the important basic reference when nitritation process is applied for MWTPs.

• Clinical and Experimental Pediatrics
• /
• v.52 no.4
• /
• pp.429-434
• /
• 2009

Purpose : Severe aspiration of the amniotic fluid is known to cause fatal respiratory distress in neonates. We conducted this study to investigate the clinical findings of severe amniotic fluid aspiration pneumonia (AFAP) in neonates and the effect of pulmonary surfactant replacement therapy (SRT). Methods : Retrospective analysis of medical records was conducted on 28 patients who received ventilator care due to severe AFAP in a neonatal intensive care unit over a 7-year period (2000-2006). Patients whose amniotic fluid was contaminated with meconium were excluded. Results : A large number of cases were term infants (82.1%) and infants born by caesarean section (85.7%), and the 1- and 5-min Apgar scores of these patients were $6.5{\pm}1.2$ and $7.5{\pm}1.3$, respectively. Soon after birth, the amount of amniotic fluid sucked out from airway below the vocal cord was $16.0{\pm}10.1$ mL. All patients received SRT with a modified bovine-derived surfactant (120 mg/kg/dose), and one dose was administered in most cases (75%). Compared with pre-SRT, the oxygenation index ($8.0{\pm}9.6$ vs. $18.9{\pm}7.3$) according to ventilator care was a significant improvement at 12 h after SRT (P<0.001). Furthermore, most cases showed radiological improvement for aeration at 12 h post-treatment. Many cases (46.4%) had cardiorespiratory complications, but their final outcomes were excellent (survival rate, 96.4%). Conclusion : AFAP may be an important cause of serious respiratory distress in near-term and term infants, and SRT seems to be an effective adjuvant therapy in mechanically ventilated neonates with severe AFAP.

• Journal of Korea Entertainment Industry Association
• /
• v.13 no.6
• /
• pp.165-173
• /
• 2019

This study aims to examine the moderating effects of band circuit training for the mortality improvement of elderly women to provide an effective exercise moderating program for the enhanced quality of life of the elderly. To achieve the purpose of this study, the moderating effects of 8 weeks of band circuit training in the Senior Fitness Tests (SFT) and Sitting Rising Tests (SRT) of elderly women ages 65 and older in Y city were examined and the following results were gained. The functional fitness of elderly women according to the moderating effects of band circuit training (sitting down in a chair and standing up, lifting 2 kg dumbbells, walking in place for 2 minutes, sitting in a chair and bending forward, hand holding behind one's back, walking back and forth for 2.44 m) and the Sitting Rising Test (SRT) displayed statistically significant interaction effects among measurement times and groups and positive improvements were shown in the test group after band circuit training moderation. These research results show that band circuit training moderation has a positive effect on functional fitness and SRT, which are associated with the mortality rate of the elderly, and thus it can be applied as an effective exercise moderation program for the improvement of quality of life through the mortality improvement of the elderly.

• Journal of Microbiology and Biotechnology
• /
• v.28 no.9
• /
• pp.1426-1432
• /
• 2018

Staphylococcus aureus causes a broad variety of diseases. The spread of multidrug-resistant S. aureus highlights the need to develop new ways to combat S. aureus infections. Sortase A (SrtA) can anchor proteins containing LPXTG binding motifs to the bacteria surface and plays a key role in S. aureus infections, making it a promising antivirulence target. In the present study, we used a SrtA activity inhibition assay to discover that isovitexin, a Chinese herbal product, can inhibit SrtA activity with an $IC_{50}$ of $28.98{\mu}g/ml$. Using a fibrinogen-binding assay and a biofilm formation assay, we indirectly proved the SrtA inhibitory activity of isovitexin. Additionally, isovitexin treatment decreased the amount of staphylococcal protein A (SpA) on the surface of the cells. These data suggest that isovitexin has the potential to be an anti-infective drug against S. aureus via the inhibition of sortase activity.

• Journal of Korean Society on Water Environment
• /
• v.26 no.3
• /
• pp.468-473
• /
• 2010

The purpose of this study is to derive the correlation between the Specific Phosphorus Release Rate (SPRR), Specific Phosphorus Uptake Rate (SPUR) and Specific Oxygen Uptake Rate (SOUR) at various Sludge Retention Time (SRT) condition in the A/O process. The laboratory scale reactor was operated on various SRT (10 day, 20 day, 30 day, 40 day). In this study, the SPRR, SPUR and SOUR tended to decrease with the SRT increase. Empirical equations was be obtained $y=4.54E-006x^2+0.0007x-0.0315$, $R^2=0.925$ (SOUR vs. SPRR) and $y=3.22E-006x^2+0.0004x-0.0173$, $R^2=0.928$ (SOUR vs. SPUR) from the relationship between SRT, SPRR and SPUR and SOUR. Therefore, the anaerobic tank design based on the research result such as SPRR, SPUR of a phosphorus design and SOUR would be possible.

• Korean Journal of Biological Psychiatry
• /
• v.9 no.2
• /
• pp.112-119
• /
• 2002

Object:This study was to investigate the difference of speech perception ability in schizophrenic patients, and depression patients in order to explore trait-dependent speech perception ability of each disorder. Methods:The speech perception ability was assessed with masked speech tracking test(MST) in schizophrenic patients(N=31), depression patients(N=25), and normal controls(N=21). The continuous performance test(CPT) and sentence repetition test(SRT) were also used for assessment of attention and working memory. Results:The schizophrenic patients showed significant impaired MST performance, compared with depressive patients and normal controls. The performances of CPT and SRT were also more impaired in schizophrenic patients. The difference of MST performances between two patient group was cancelled out after consideration of differences in CPT & SRT performances. Conclusions:These results imply that schizophrenic patients have the impaired speech perception ability compared with depressive patients and normal controls. But speech perception ability was significantly influenced with CPT and SRT. For evaluation of pure speech perception ability, the more elaborate controlled study that excluded factors such as attention, working memory and intelligence is needed.

• Journal of Korean Society for Atmospheric Environment
• /
• v.21 no.E2
• /
• pp.41-48
• /
• 2005

A novel hybrid system composed of a biotrickling filter and an activated sludge reactor was investigated under the conditions of four different SRTs (sludge retention times). The performance of the hybrid reactor was found to be directly comparable among the four different sludge ages. Discernible differences in the removal performance were observed among four different SRTs of 2, 4, 6, and 8 days. High removal efficiency was achieved by continuous circulation of activated sludge over the immobilized mixture culture, which allowed on pH control, addition of nutrients, and removal of paint VOCs (volatile organic compounds). The results also showed that the removal efficiency for a given pollutant depends on the activity of microorganisms based on the SRT. As the SRT increased gradually from 2 to 8 days, the average removal performance decreased. The highest removal rate was achieved at the SRT of 2 days at which the highest OUR (oxygen uptake rate), $6.1mg-O_2/liter-min$ was measured. Biological activity in the recycle microbes decreased to a much lower level, $3.6mg-O_2/liter-min$ at a SRT of 8 days. It is thus believed that young microorganisms were more active and more efficient for the VOCs removal of low concentrations and high flow rates. The apparent correlation of $R^2=0.996$ between the average removal efficiency and the average OUR at each SRTs suggests that VOCs degradation by young cells significantly affected the overall removal efficiency for the tested SRTs.

• Journal of Korean Society of Water and Wastewater
• /
• v.27 no.6
• /
• pp.815-826
• /
• 2013

Using a developed mathematical model and calibrated kinetic constants, numerical experiments for a aerobic digestion of wastewater sludge by SBR aerobic digestion process combined with ultrasonication (USSBR) were performed in this study. It simulated well the phenomena of the decomposition of particulate organics and the release of organic nitrogen and transformation. To achieve 40 % of particulate organics removal, USSBR process requires only 6 days of SRT and 14 W/L of ultrasonic power whereas SBR aerobic digestion process requires 12 days of SRT. Based on the model simulation results, an empirical equation was presented here. This equation will be used to predict digestion efficiency for the given variables of SRT and ultrasonic power dose. USSBR aerobic digestion process can reduce the nitrogen concentration. The optimal operation strategy for the simultaneous removal of solids and soluble nitrogen in this process is estimated to 7 days of SRT with 14 W/L of ultrasonic power dose while anoxic period was 6 hours out of 24 hours of cycle time. In this condition, 40 % of particulate organics as well as 36 % of total nitrogen will be removed and the soluble nitrogen concentration of the centrate will be lower less then 40 mg/L.

• Membrane and Water Treatment
• /
• v.6 no.6
• /
• pp.501-512
• /
• 2015

A laboratory-scale submerged membrane bioreactor (MBR) was continuously operated for 100 d at an infinite sludge retention time (SRT) with the aim of identifying possible relation between the filterability of mixed liquor and sludge properties, such as extracellular polymeric substances (EPS), soluble microbial products (SMP), viscosity of mixed liquor, zeta potential of flocs and particle size distributions (PSD). Research results confirmed that MBR can operate with a complete sludge retention ensuring good treatment performances for COD and $NH_3-N$. However, the long term operation (about 40 d) of MBR with no sludge discharge had a negative influence on sludge filterability, and an increase in membrane fouling rates with the time was observed. There as a strong correlation between the sludge filterability and the fouling rate. Among the different sludge properties parameters, the concentration SMP and EPS had a more closely correlation with the sludge filterability. The concentrations of SMP, especially SMP with MW above 10 kDa, had a strong direct correlation to the filterability of mixed sludge. The protein fractions in EPS were biodegradable and available for microorganism metabolism after about 60 days, and the carbohydrates in EPS had a significantly negative effect on sludge filterability in MBR at an infinite SRT.

• Journal of Microbiology and Biotechnology
• /
• v.32 no.10
• /
• pp.1284-1291
• /
• 2022

The rise of methicillin-resistant Staphylococcus aureus (MRSA) has resulted in significant morbidity and mortality, and clinical treatment of MRSA infections has become extremely difficult. Sortase A (SrtA), a virulence determinant that anchors numerous virulence-related proteins to the cell wall, is a prime druggable target against S. aureus infection due to its crucial role in the pathogenicity of S. aureus. Here, we demonstrate that isovitexin, an active ingredient derived from a variety of traditional Chinese medicines, can reversibly inhibit SrtA activity in vitrowith a low dose (IC₅₀=24.72 ㎍/ml). Fluorescence quenching and molecular simulations proved the interaction between isovitexin and SrtA. Subsequent point mutation experiments further confirmed that the critical amino acid positions for SrtA binding to isovitexin were Ala-92, Ile-182, and Trp-197. In addition, isovitexin treatment dramatically reduced S. aureus invasion of A549 cells. This study shows that treatment with isovitexin could alleviate pathological injury and prolong the life span of mice in an S. aureus pneumonia model. According to our research, isovitexin represents a promising lead molecule for the creation of anti-S. aureus medicines or adjuncts.