77 results on '"Chulmin Lee"'
Search Results
2. Attitudes Toward Transgender People Among Medical Students in South Korea
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Sa Ra Lee, MD, PhD, Min-A Kim, MD, Mun Nyeong Choi, MD, Suyeon Park, MS, Jaehyun Cho, MD, Chulmin Lee, MD, PhD, and Eun Sil Lee, MD, PhD
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Transgender ,Attitudes ,Genderism and Transphobia Scale ,Attitudes Toward Transgendered Individuals Scale ,Education ,Medicine - Abstract
Introduction: Interventions aimed at changing knowledge, attitudes, and beliefs of resident physicians and medical students have been made to incite a significant positive increase in attitudes, comfort, and knowledge toward the lesbian, gay, bisexual, and transgender (LGBT) community, as well as increased levels of competency among participants. Aim: To use insights from the attitudes of medical students toward transgender people and demonstrate that adding lectures on transgenderism would make the medical school curricula more comprehensive and trans-inclusive by improving overall attitudes toward the LGBT community. Methods: A total of 49 medical students completed the preintervention survey with the Genderism and Transphobia Scale and Attitudes Toward Transgendered Individuals Scale, and then took a class on transgenderism, whereas 39 individuals completed the 4-week postintervention survey following the same measures. Main Outcome Measure: Three items of survey were demographic characteristics, the Genderism and Transphobia Scale, and the Attitude Toward Transgender Individuals Scale. Results: Although there was no significant difference in mean score between the preintervention and postintervention surveys, those who had minority individuals as peers and those who had previous LGBT-related education showed significantly positive attitudes than those without after the lecture. As a result of analyzing all the data from the pre/postintervention surveys, being of the female gender and having minority individuals as peers positively affected attitude. Conclusion: Although there was no significant attitude change after the lecture, those who had previous LGBT-related education showed significantly positive attitudes at pre/postintervention surveys than those without. These findings suggest that raising awareness and education should be continued for a positive attitude toward more vulnerable groups such as the LGBT. Given the lack of studies on transgenderism that involve students in the medical profession in South Korea, this study shows the necessity of curricula creation of transgenderism education. This study aims to serve as a basis for curricula creation and student guidance that will help creating more positive attitudes toward sexual and gender minorities.Lee SR, Kim M-A, Choi MN, et al. Attitudes Toward Transgender People Among Medical Students in South Korea. Sex Med 2021;9:100278.
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- 2021
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3. What to do with troublesome hot flush?
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Su Hyun Chae, Chulmin Lee, Heung Yeol Kim, and Ji Young Lee
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hot flush ,treatment ,Medicine (General) ,R5-920 - Abstract
Hot flush (hot flush or facial flush) is the most frequent symptom experienced by women of peri-menopausal age. It may appear on women or even men after surgery or chemotherapy. Hot flush is one of the biggest reason for women to undergo hormone replacement therapy (HRT). It also crucially affects various aspects of life quality such as occupation, social life, daily routine and health awareness. The most effective and fundamental remedy for hot flush is HRT. However, a few women is not responsive to HRT and investigation to elucidate other causes of hot flush is warranted, especially in elderly. The contraindications such as breast cancer mandates other modality of treatment. Variety of treatment for hot flush other than HRT will be discussed herein.
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- 2018
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4. Practical Considerations of Wastewater–Seawater Integrated Reverse Osmosis: Design Constraint by Boron Removal
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Chulmin Lee, Yesol Kang, Dong-Ho Kim, and In S. Kim
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reverse osmosis ,hybrid desalination ,boron removal ,Chemical technology ,TP1-1185 ,Chemical engineering ,TP155-156 - Abstract
The wastewater–seawater (WW-SW) integrated reverse osmosis (RO) process has gained much attention in and out of academia due to its energy saving capability, economic benefits, and sustainability. The other advantage of this process is to reduce boron concentration in the RO permeate that can exclude the post-treatment process. However, there are multiple design constraints regarding boron removal that restrict process design in the WW-SW integrated system. In this study, uncertainties in design factors of the WW-SW integrated system in consideration of boron removal have been explored. In comprehensive consideration of the blending ratio of between WW and SW, regulatory water quality standard, specific energy consumption (SEC), specific water cost, and RO recovery rate, a range of 15,000~20,000 mg/L feed turned out to be the most appropriate. Furthermore, boron rejection tests with SWRO (seawater reverse osmosis) and BWRO (brackish water reverse osmosis) membranes under actual WW-SW integration found a critical reduction in boron rejection at less than 20 bar of operating pressure. These findings emphasize the importance of caution in the use of BWRO membranes in the WW-SW integrated RO system.
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- 2021
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5. Performance Evaluation and Fouling Propensity of Forward Osmosis (FO) Membrane for Reuse of Spent Dialysate
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Chaeyeon Kim, Chulmin Lee, Soo Wan Kim, Chang Seong Kim, and In S. Kim
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hemodialysis ,forward osmosis ,spent dialysate ,PA-TFC membrane ,membrane fouling ,Chemical technology ,TP1-1185 ,Chemical engineering ,TP155-156 - Abstract
The number of chronic renal disease patients has shown a significant increase in recent decades over the globe. Hemodialysis is the most commonly used treatment for renal replacement therapy (RRT) and dominates the global dialysis market. As one of the most water-consuming treatments in medical procedures, hemodialysis has room for improvement in reducing wastewater effluent. In this study, we investigated the technological feasibility of introducing the forward osmosis (FO) process for spent dialysate reuse. A 30 LMH of average water flux has been achieved using a commercial TFC membrane with high water permeability and salt removal. The water flux increased up to 23% with increasing flowrate from 100 mL/min to 500 mL/min. During 1 h spent dialysate treatment, the active layer facing feed solution (AL-FS) mode showed relatively higher flux stability with a 4–6 LMH of water flux reduction while the water flux decreased significantly at the active layer facing draw solution (AL-DS) mode with a 10–12 LMH reduction. In the pressure-assisted forward osmosis (PAFO) condition, high reverse salt flux was observed due to membrane deformation. During the membrane filtration process, scaling occurred due to the influence of polyvalent ions remaining on the membrane surface. Membrane fouling exacerbated the flux and was mainly caused by organic substances such as urea and creatinine. The results of this experiment provide an important basis for future research as a preliminary experiment for the introduction of the FO technique to hemodialysis.
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- 2020
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6. Spatial and Temporal Exposure Assessment to PM2.5 in a Community Using Sensor-Based Air Monitoring Instruments and Dynamic Population Distributions
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Jinhyeon Park, Wondeuk Jo, Mansu Cho, Jeongil Lee, Hunjoo Lee, SungChul Seo, Chulmin Lee, and Wonho Yang
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exposure surveillance system ,fine particulate matter ,dynamic population distribution ,population exposure ,time–activity pattern ,Meteorology. Climatology ,QC851-999 - Abstract
This research was to conduct a pilot study for two consecutive days in order to assess fine particulate matter (PM2.5) exposure of an entire population in a community. We aimed to construct a surveillance system by analyzing the observed spatio-temporal variation of exposure. Guro-gu in Seoul, South Korea, was divided into 2,204 scale grids of 100 m each. Hourly exposure concentrations of PM2.5 were modeled by the inverse distance weighted method, using 24 sensor-based air monitoring instruments and the indoor-to-outdoor concentration ratio. Population distribution was assessed using mobile phone network data and indoor residential rates, according to sex and age over time. Exposure concentration, population distribution, and population exposure were visualized to present spatio-temporal variation. The PM2.5 exposure of the entire population of Guro-gu was calculated by population-weighted average exposure concentration. The average concentration of outdoor PM2.5 was 42.1 µg/m3, which was lower than the value of the beta attenuation monitor measured by fixed monitoring station. Indoor concentration was estimated using an indoor-to-outdoor PM2.5 concentration ratio of 0.747. The population-weighted average exposure concentration of PM2.5 was 32.4 µg/m3. Thirty-one percent of the population exceeded the Korean Atmospheric Environmental Standard for PM2.5 over a 24 h average period. The results of this study can be used in a long-term aggregate and cumulative PM2.5 exposure assessment, and as a basis for policy decisions on public health management among policymakers and stakeholders.
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- 2020
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7. Accuracy of three dimensional ultrasound and treatment outcomes of intrauterine adhesion in infertile women
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Min Jeong Kim, Youngjin Lee, Chulmin Lee, Sungwook Chun, Ari Kim, Heung Yeol Kim, and Ji Young Lee
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fertility ,intrauterine adhesion ,pregnancy ,three-dimensional transvaginal ultrasound ,uterine synechiae ,Gynecology and obstetrics ,RG1-991 - Abstract
Objective: To determine the accuracy and usefulness of three-dimensional transvaginal ultrasound (3D-TVUS) in diagnosing intrauterine adhesion (IUA) and to evaluate treatment outcomes associated with fertility. Materials and Methods: IUA patients (110) underwent hysteroscopy to definitively diagnose and treat adhesiolysis. Morphologic characteristics of endometrium suggesting IUA, such as marginal irregularity, thinning, defects, obliteration, fibrosis, and calcification, were identified and recorded by 3D-TVUS. The sensitivity of 3D-TVUS findings and the attainment of postoperative fertility were evaluated prospectively. The clinical records were followed up for 2 years for obstetrical outcomes and analyzed. Results: On comparing the findings of 3D-TVUS with those of hysteroscopy in 110 patients, 45 (88.23%) patients were confirmed as IUA by hysteroscopy among 51 (46.36%) patients, with one finding in 3D-TVUS; 42 (97.67%) patients were confirmed among 43 (39.09%) patients with two findings; and 16 (100%) patients were confirmed among 16 (14.55%) patients with over three findings. A pregnancy rate of eight out of 47 (17.02%) was achieved in patients who desired fertility. Conclusion: 3D-TVUS assessment of the uterus provides an accurate depiction of adhesion and extent of cavity damage in patients with suspected IUA.
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- 2015
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8. Pelvic actinomycosis with abundant ascites, pleural effusion, and lymphadenopathy diagnosed with endometrial biopsy and treated with medication only
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Myounghwan Kim, Jikung Ko, and Chulmin Lee
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actinomycosis ,ascites ,intrauterine contraceptive device ,ovarian cancer ,Gynecology and obstetrics ,RG1-991 - Abstract
Objective: Pelvic actinomycosis almost always presents as a “dry” type, and pelvic actinomycosis with ascites is extremely rare. We present an unusual case of pelvic actinomycosis with ascites, pleural effusion, and lymphadenopathy. Because of these atypical clinical features, a malignant process such as ovarian cancer or peritoneal carcinomatosis was suspected, but an endometrial biopsy revealed pelvic actinomycosis, which was treated without surgical intervention. Case report: A 50-year-old Korean woman presented to our clinic with a 3-month history of abdominal pain and weight loss. An abdominopelvic computed tomography scan demonstrated ascites, pleural effusion, bilateral adnexal tubular structures, several enlarged lymph nodes in the paraaortic area, and diffuse peritoneal infiltration. Ultrasonography showed fluid collections measuring 2.7 cm in the cul-de-sac, 2.42 cm in the right paracolic gutter, and 3.13 cm in the left paracolic gutter. Endometrial/endocervical specimens showed marked chronic inflammation with sulfur granules, with a colony of filamentous organisms consistent with Actinomyces infection. The patient underwent antibiotic treatment for 6 months and recovered without complications or adverse events in the 13 months of follow up. Conclusion: Pelvic actinomycosis should always be considered in patients with a pelvic mass and peritoneal infiltration, especially in the presence of intrauterine device use, despite the fact that abundant ascites, pleural effusion, and lymphadenopathy almost never accompany pelvic actinomycosis. Endometrial/endocervical biopsy may yield a diagnosis without an invasive procedure and should be performed. Because of the excellent response to penicillin, medical treatment alone is an effective method to eradicate pelvic actinomycosis without the need for surgical intervention.
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- 2014
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9. 'The Subjective Perception Types of Social Workers on Community Care'
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Hansol Kim, Chulmin Lee, and Hyuntae Jung
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- 2022
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10. Radiotherapy versus OBServation in intErmediate risk patients after Radical hysterectomy for early cerVical cancer (R-OBSERV): ancillary analysis of a Korean Gynecologic Group Study (KGOG1028)
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Seung-Hyuk Shim, Myong Cheol Lim, Moon-Hong Kim, Yun Hwan Kim, Eun Seop Song, Seok Ju Seong, Dong Hoon Suh, Jong-Min Lee, Chulmin Lee, and Chel Hun Choi
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- 2023
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11. A Study on the Influence on the Elderly’s Suicidal Thoughts
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Dongmoon Yeum and Chulmin Lee
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General Medicine - Published
- 2021
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12. Effect of porcine placental extract on menopausal symptoms in postmenopausal women: A prospective, randomized, double-blind, placebo-controlled trial
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Hoon Choi, Chulmin Lee, Sang-Hee Yoon, and Ji Young Lee
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medicine.medical_specialty ,Swine ,Placental extract ,Placebo-controlled study ,Administration, Oral ,Overweight ,lcsh:Gynecology and obstetrics ,Placebo group ,Body Mass Index ,Double blind ,Double-Blind Method ,Oral administration ,Internal medicine ,Republic of Korea ,medicine ,Animals ,Humans ,Placental Extracts ,lcsh:RG1-991 ,Menopausal symptoms ,Postmenopausal women ,business.industry ,Porcine placental extract ,Obstetrics and Gynecology ,Middle Aged ,Female ,Menopause ,medicine.symptom ,business ,Body mass index - Abstract
Objectives: To determine the effect of oral administration of porcine placental extract (PPE) on the menopausal symptoms of Korean women. Materials and methods: This study was a multicenter, randomized double-blind placebo-controlled trial. A hundred menopausal Korean women were randomly allocated either to the PPE 400 mg per day or the control group during 12 weeks of the study period. Menopausal symptoms were evaluated using the Kupperman Index (KMI). Results: The KMI decreased after 12 weeks in both groups; however, the difference in the changes was not statistically significant. Among overweight or obese women whose body mass index (BMI) was 23 kg/m2 or higher, the KMI decreased more significantly in the PPE group than placebo group after 12 weeks (−18.52 ± 9.09 vs −11.40 ± 10.68, P
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- 2020
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13. Gabapentin for the treatment of hot flushes in menopause: a meta-analysis
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Sang-Hee Yoon, Chulmin Lee, Ji Young Lee, Hyojin Lee, and Soo-Nyung Kim
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medicine.medical_specialty ,Gabapentin ,General Mathematics ,030209 endocrinology & metabolism ,Placebo ,law.invention ,03 medical and health sciences ,0302 clinical medicine ,Randomized controlled trial ,law ,Internal medicine ,medicine ,Humans ,Adverse effect ,030219 obstetrics & reproductive medicine ,business.industry ,Applied Mathematics ,Obstetrics and Gynecology ,Odds ratio ,medicine.disease ,Menopause ,Tolerability ,Strictly standardized mean difference ,Hot Flashes ,Female ,business ,medicine.drug - Abstract
OBJECTIVE Gabapentin is used to treat vasomotor symptoms (VMS) in postmenopausal women with contraindications to hormonal therapy or who prefer alternatives. We investigated the efficacy and tolerability of gabapentin for treating menopausal hot flushes via a meta-analysis. METHODS We searched the PubMed, MEDLINE, EMBASE, and CENTRAL databases for English-language articles published until June, 2018. The following search terms were used: "menopause," "hot flushes," "vasomotor symptoms," "gabapentin," and "non-hormonal therapy." Primary outcomes were frequency, duration, and composite score of hot flushes. Secondary outcomes were adverse effects and dropout rate. We estimated the standardized mean difference (SMD) and combined odds ratio (OR) using fixed or random-effects models, depending on study heterogeneity. Subgroup and meta-regression analyses of gabapentin dosage were performed. RESULTS We included seven randomized controlled trials that compared single-agent gabapentin with placebo for treating hot flushes in the meta-analysis. Women who received gabapentin reported a significantly greater reduction in the frequency (SMD 2.99 [95% confidence interval 2.01-3.98], P
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- 2020
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14. Effect of Twisted Hollow Fiber Membranes in a Module: Computational Fluid Dynamics Simulations on the Pressure and Concentration Profile of the Module in the forward Osmosis
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Chulmin Lee, Suhun Kim, and In S. Kim
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Membrane ,Materials science ,business.industry ,Forward osmosis ,General Medicine ,Fiber ,Computational fluid dynamics ,Composite material ,business - Published
- 2020
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15. Modeling of flow uniformity by installing inlet distributor within the inflow part of a pressurized module using computational fluid dynamics
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Chulmin Lee, Changkyoo Choi, and In S. Kim
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geography ,Environmental Engineering ,Materials science ,geography.geographical_feature_category ,Flow distribution ,business.industry ,Flow (psychology) ,Distributor ,Flux ,02 engineering and technology ,Inflow ,Mechanics ,Computational fluid dynamics ,021001 nanoscience & nanotechnology ,Inlet ,020401 chemical engineering ,Installation ,0204 chemical engineering ,0210 nano-technology ,business - Abstract
Uniform flow distribution is a significant parameter for designing pressurized membrane modules because non-uniform flow distribution can cause serious local flux and fouling problems within a module. Thus, this study investigated the fluid behavior with regards to the evenness of water distribution using newly designed inlet distributors in the inflow part of a pressurized membrane module. From the results of velocity and pressure at the cross-sectional and outlet planes, we confirmed that a conventional membrane module with no distributor (non-distributor) had fluid that was concentrated at the central part. Case 1, which had a cross-shaped distributor, reduced the central concentration tendency, and Case 2, which had a round-shaped distributor, displayed a relatively uniform flow based on the velocity, pressure, flux, and standard deviation data. Here, the non-uniformity coefficient (N) and energy utilization (η) for Cases 1 and 2 showed a lower non-uniformity coefficient (0.030 and 0.017, respectively) than for the Non-distributor (0.039). The energy utilization of Cases 1 and 2 were higher (1.35e-0.5 and 1.46e-05) than the Non-distributor (1.64e-05). Overall, we confirmed that the inlet distributors led to increased evenness of flow distribution within an inflow part.
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- 2020
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16. Performance analysis of serially-connected membrane element for pressure-assisted forward osmosis: wastewater reuse and seawater desalination
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Rusnang Syamsul Adha, Nguyen Thanh Tin, Chulmin Lee, and In S. Kim
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Membrane ,Wastewater reuse ,Seawater desalination ,Forward osmosis ,Environmental engineering ,Environmental science - Published
- 2020
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17. Study on the monitoring of indoor air quality for 24 hours: life pattern of asthma patients based on IoT
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Sun Ju Nam Goung, HyoungJun Kim, SungChul Seo, KilYong Choi, ChaeBong Kim, and Chulmin Lee
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Indoor air quality ,business.industry ,Life Pattern ,Environmental health ,medicine ,Environmental science ,Internet of Things ,business ,medicine.disease ,Indoor air pollutants ,Asthma - Published
- 2019
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18. Prognostic Model for Survival and Recurrence in Patients with Early-Stage Cervical Cancer: A Korean Gynecologic Oncology Group Study (KGOG 1028)
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E Sun Paik, Myong Cheol Lim, Moon Hong Kim, Chel Hun Choi, Eun Seop Song, Jong Min Lee, Seok Ju Seong, Dong Hoon Suh, Chulmin Lee, and Yun Hwan Kim
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0301 basic medicine ,Oncology ,Cancer Research ,medicine.medical_specialty ,Uterine cervical neoplasms ,Disease-free survival ,Gynecologic oncology ,Disease ,Kaplan-Meier Estimate ,03 medical and health sciences ,0302 clinical medicine ,Recurrence ,Internal medicine ,Republic of Korea ,medicine ,Humans ,In patient ,Public Health Surveillance ,Stage (cooking) ,Neoplasm Staging ,Proportional Hazards Models ,Cervical cancer ,Prognostic factor ,business.industry ,Area under the curve ,Survival analyses ,Prognoses ,Reproducibility of Results ,medicine.disease ,Prognosis ,Survival Analysis ,Survival Rate ,030104 developmental biology ,Lymphatic system ,ROC Curve ,030220 oncology & carcinogenesis ,Area Under Curve ,Lymphatic Metastasis ,Cohort ,Original Article ,Female ,business - Abstract
PURPOSE We aimed to develop and validate individual prognostic models in a large cohort of cervical cancer patients that were primarily treated with radical hysterectomy. Materials and Methods We analyzed 1,441 patients with early-stage cervical cancer treated between 2000 and 2008 from the Korean Gynecologic Oncology Group multi-institutional cohort: a train cohort (n=788) and a test cohort (n=653). Models predicting the risk for overall survival (OS), disease- free survival (DFS), lymphatic recurrence and hematogenous recurrence were developed using Cox analysis and stepwise backward selection and best-model options. The prognostic performance of each model was assessed in an independent patient cohort. Model-classified risk groups were compared to groups based on traditional risk factors. RESULTS Independent risk factors for OS, DFS, lymphatic recurrence, and hematogenous recurrence were identified for prediction model development. Different combinations of risk factors were shown for each outcome with best predictive value. In train cohort, area under the curve (AUC) at 2 and 5 years were 0.842/0.836 for recurrence, and 0.939/0.882 for OS. When applied to a test cohort, the model also showed accurate prediction result (AUC at 2 and 5 years were 0.799/0.723 for recurrence, and 0.844/0.806 for OS, respectively). The Kaplan-Meier plot by proposed model-classified risk groups showed more distinctive survival differences between each risk group. CONCLUSION We developed prognostic models for OS, DFS, lymphatic and hematogenous recurrence in patients with early-stage cervical cancer. Combining weighted clinicopathologic factors, the proposed model can give more individualized predictions in clinical practice.
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- 2019
19. Numerical study of fluid behavior on protruding shapes within the inlet part of pressurized membrane module using computational fluid dynamics
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No-Suk Park, In S. Kim, Chulmin Lee, and Changkyoo Choi
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geography ,Environmental Engineering ,Materials science ,geography.geographical_feature_category ,business.industry ,02 engineering and technology ,Mechanics ,Computational fluid dynamics ,021001 nanoscience & nanotechnology ,Inlet ,Membrane ,020401 chemical engineering ,Flow velocity ,0204 chemical engineering ,0210 nano-technology ,business ,Fluid pressure - Abstract
This study analyzes the velocity and pressure incurred by protruding shapes installed within the inlet part of a pressurized membrane module during operation to determine the fluid flow distribution. In this paper, to find the flow distribution within a module, it investigates the velocity and pressure values at cross-sectional and outlet planes, and 9 sections classified on outlet plane using computational fluid dynamics. From the Reynolds number (Re), the fluid flow was estimated to be turbulent when the Re exceeded 4,000. In the vertical cross-sectional plane, shape 4 and 6 (round-type protrusion) showed the relatively high velocity of 0.535 m/s and 0.558 m/s, respectively, indicating a uniform flow distribution. From the velocity and pressure at the outlet, shape 4 also displayed a relatively uniform fluid velocity and pressure, indicating that fluid from the inlet rapidly and uniformly reached the outlet, however, from detailed data of velocity, pressure and flowrate obtained from 9 sections at the outlet, shape 6 revealed the low standard deviations for each section. Therefore, shape 6 was deemed to induce the ideal flow, since it maintained a uniform pressure, velocity and flowrate distribution.
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- 2019
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20. Practical Considerations of Wastewater-Seawater Integrated Reverse Osmosis: Design Constraint by Boron Removal
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Yesol Kang, Chulmin Lee, Dong-Ho Kim, and In S. Kim
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chemistry.chemical_element ,Filtration and Separation ,Process design ,02 engineering and technology ,010501 environmental sciences ,lcsh:Chemical technology ,01 natural sciences ,hybrid desalination ,Article ,reverse osmosis ,020401 chemical engineering ,Chemical Engineering (miscellaneous) ,lcsh:TP1-1185 ,lcsh:Chemical engineering ,0204 chemical engineering ,Process engineering ,Boron ,Reverse osmosis ,0105 earth and related environmental sciences ,Brackish water ,business.industry ,Process Chemistry and Technology ,lcsh:TP155-156 ,Membrane ,Wastewater ,chemistry ,Environmental science ,Seawater ,boron removal ,Water quality ,business - Abstract
The wastewater–seawater (WW-SW) integrated reverse osmosis (RO) process has gained much attention in and out of academia due to its energy saving capability, economic benefits, and sustainability. The other advantage of this process is to reduce boron concentration in the RO permeate that can exclude the post-treatment process. However, there are multiple design constraints regarding boron removal that restrict process design in the WW-SW integrated system. In this study, uncertainties in design factors of the WW-SW integrated system in consideration of boron removal have been explored. In comprehensive consideration of the blending ratio of between WW and SW, regulatory water quality standard, specific energy consumption (SEC), specific water cost, and RO recovery rate, a range of 15,000~20,000 mg/L feed turned out to be the most appropriate. Furthermore, boron rejection tests with SWRO (seawater reverse osmosis) and BWRO (brackish water reverse osmosis) membranes under actual WW-SW integration found a critical reduction in boron rejection at less than 20 bar of operating pressure. These findings emphasize the importance of caution in the use of BWRO membranes in the WW-SW integrated RO system.
- Published
- 2021
21. Sarcopenia as a Predictor of Prognosis in Early Stage Ovarian Cancer
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Soo Nyung Kim, Sochung Chung, Seung-Hyuk Shim, Sang Hee Yoon, Su Hyun Chae, Sun Joo Lee, Chulmin Lee, and Ji Young Lee
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Oncology ,Adult ,medicine.medical_specialty ,Prognostic factor ,Sarcopenia ,Adolescent ,Kaplan-Meier Estimate ,03 medical and health sciences ,Young Adult ,0302 clinical medicine ,Internal medicine ,Overall survival ,Medicine ,Humans ,In patient ,030212 general & internal medicine ,Oncology & Hematology ,Stage (cooking) ,Prospective cohort study ,Muscle, Skeletal ,Aged ,Neoplasm Staging ,Proportional Hazards Models ,Retrospective Studies ,Aged, 80 and over ,Ovarian Neoplasms ,business.industry ,Proportional hazards model ,Early Stage Ovarian Cancer ,Overall Survival ,Prognostic Factor ,General Medicine ,Middle Aged ,medicine.disease ,Prognosis ,Original Article ,Female ,business ,Ovarian cancer ,Tomography, X-Ray Computed ,human activities - Abstract
Background To identify sarcopenia as a predictive prognostic factor of ovarian cancer in terms of survival outcome in patients with early-stage ovarian cancer. Methods Data of Konkuk University Medical Center from March 2002 to December 2017 were reviewed retrospectively. Eighty-two patients who underwent surgery due to early-stage (International Federation of Gynecology and Obstetrics stage I/II) ovarian cancer and had computed tomography (CT) images taken at the initial diagnosis were included. The initial CT scan images were analyzed with SliceOmatic software (TomoVision). A sarcopenia cutoff value was defined as a skeletal muscle index of ≤ 38.7 cm2/m2. Overall survival (OS) times were compared according to the existence of sarcopenia, and subgroup analyses were performed. Results A Kaplan-Meier analysis showed a significant survival disadvantage for patients with early-stage ovarian cancer when they had sarcopenia (P < 0.001; log-rank test). Sarcopenia remained a significant prognostic factor for OS in early-stage ovarian cancer, in a Cox proportional hazards model regression analysis (HR, 21.9; 95% CI, 2.0–199.9; P = 0.006). Conclusion This study demonstrated that sarcopenia was predictive of OS in patients with early-stage ovarian cancer. Further prospective studies with a larger number of patients are warranted to determine the extent to which sarcopenia can be used as a prognostic factor in ovarian cancer., Graphical Abstract
- Published
- 2020
22. An Improved Configuration of Vertical-Flow Mesh Tube Filters for Seawater Pretreatment: Performance, Cleaning, and Energy Consumption
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Sang-Jun Ahn, Dong-Ho Kim, Thanh-Tin Nguyen, Chulmin Lee, In S. Kim, Changkyoo Choi, Hee-Jong Son, and Rusnang Syamsul Adha
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Materials science ,lcsh:Hydraulic engineering ,Sedimentation (water treatment) ,Dissolved air flotation ,Geography, Planning and Development ,Analytical chemistry ,02 engineering and technology ,010501 environmental sciences ,Aquatic Science ,01 natural sciences ,Biochemistry ,porous filter bed ,law.invention ,lcsh:Water supply for domestic and industrial purposes ,020401 chemical engineering ,law ,lcsh:TC1-978 ,Deposition (phase transition) ,0204 chemical engineering ,Porosity ,mesh tube filtration ,Filtration ,0105 earth and related environmental sciences ,Water Science and Technology ,lcsh:TD201-500 ,roughing filters ,specific energy consumption ,Filter (aquarium) ,suspended particles ,Seawater ,Porous medium - Abstract
Roughing filters are types of porous media filter used in pretreatment systems where the raw water contains a large amount of suspended particles (SPs) and organic matter. Mesh tube filtration (MTF) media are roughing-filter media composed of low-density polyethylene used for SP removal during wastewater treatment. In this study, we present an improved MTF design&mdash, a porous filter bed (PFB), which exhibits superior SP removal performance compared to conventional MTF media. We then compare the applicability of MTF and PFB to both the primary pretreatment process for seawater desalination and the water reuse process. In bench-scale SP removal experiments, PFB shows removal rates of 46.7%, 68.0%, 67.6%, and 68.4% at hydraulic retention times of 15, 20, 30, and 60 min, respectively, which are better than those of MTF. The specific energy consumption (SEC) of batch dissolved air flotation (DAF) was known to range from 0.035 to 0.047 kWh/m3, whereas the SEC calculated for pilot-scale MTF and PFB is 0.027 kWh/m3 and minimum energy for influent supply, respectively. This suggests that PFB can compete with DAF as a primary pretreatment process. MTF predominantly removes SPs by sedimentation, whereas SP removal in PFB typically occurs via deposition of SPs on the mesh tube media.
- Published
- 2020
23. The Prognostic Model of Pre-Treatment Complete Blood Count (CBC) for Recurrence in Early Cervical Cancer
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Chel Hun Choi, Myong Cheol Lim, Yun Hwan Kim, Eun Seop Song, Seok Ju Seong, Joseph J Noh, Dong Hoon Suh, Moon-Hong Kim, Jong Min Lee, and Chulmin Lee
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Oncology ,medicine.medical_specialty ,complete blood count ,cervical cancer ,lcsh:Medicine ,Article ,03 medical and health sciences ,0302 clinical medicine ,White blood cell ,Internal medicine ,parasitic diseases ,medicine ,Stage (cooking) ,Cervix ,Cervical cancer ,Univariate analysis ,Predictive marker ,medicine.diagnostic_test ,business.industry ,lcsh:R ,statistical model ,Complete blood count ,General Medicine ,medicine.disease ,medicine.anatomical_structure ,030220 oncology & carcinogenesis ,Adenocarcinoma ,prognosis ,business ,030215 immunology - Abstract
The aim of the present study was to investigate the prognostic role of the pre-treatment complete blood count (CBC) profile as a predictive marker of survival, recurrence, and death in early stage squamous cell carcinoma and adenocarcinoma of the cervix. The pre-treatment CBC profiles of the patients from nine tertiary medical centers in South Korea who were treated surgically for early stage cervical cancer were reviewed. Statistical models by the Akaike&rsquo, s information criterion (AIC) were developed using CBC profiles to calculate individuals&rsquo, risk scores for clinical outcomes. A total of 1443 patients were included in the study and the median follow-up was 63.7 months with a range of 3&ndash, 183 months. Univariate analyses identified the components of CBC that were significantly related to clinical outcomes including white blood cell (WBC), hemoglobin, neutrophil, and platelet levels. The models developed using CBC profiles and the conventional clinical predictive factors provided individuals&rsquo, risk scores that were significantly better in predicting clinical outcomes than the models using the conventional clinical predictive factors alone. Pre-treatment CBC profiles including WBC, hemoglobin, neutrophil, lymphocyte, and platelet levels were found to be a potential biomarker for survival prognosis in early cervical cancer.
- Published
- 2020
24. Effect of Spacer Configuration on the Characteristics of FO Membranes: Alteration of Permeation Characteristics by Membrane Deformation and Concentration Polarization
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Jaewon Jang, Nguyen Thanh Tin, Suhun Kim, Chuyang Y. Tang, In S. Kim, and Chulmin Lee
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Osmosis ,Materials science ,Membranes, Artificial ,General Chemistry ,010501 environmental sciences ,Permeation ,01 natural sciences ,Water Purification ,Membrane ,Chemical engineering ,Osmotic Pressure ,Scientific method ,Hydrodynamics ,Pressure ,Environmental Chemistry ,Membrane deformation ,Filtration ,0105 earth and related environmental sciences ,Concentration polarization - Abstract
Membrane deformation is a significant problem in osmotically driven membrane processes, as it restricts practical operating conditions and reduces overall process performance due to unfavorable alteration of membrane permeation characteristics. In this respect, a spacer plays a crucial role, as it dictates the form and extent of membrane deformation in association with concentration polarization (CP), which is also influenced by spacer-induced hydrodynamic behavior near the membrane surface. These two roles of spacers on membrane permeation characteristics are inherently inseparable with the coexistence of hydraulic and osmotic pressures. Here, we suggest a novel analytical method to differentially quantify the proportions of effective osmotic pressure drop caused by membrane deformation and CP. Furthermore, we tested two different FO membranes with three different spacer configurations to define and discuss different forms of membrane deformation and their effects on membrane permeation characteristics. The differential analysis revealed the effect of spacer configuration on effective osmotic pressure drop in membrane deformation (up to ∼201% of variation) is much greater than that in CP (up to ∼20.1% of variation). In addition, a combined configuration of a feed spacer and tricot spacer demonstrated its ability of mitigating membrane deformation with lower selectivity loss and channel pressure drop under pressurization.
- Published
- 2020
25. What to do with troublesome hot flush?
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Heung Yeol Kim, Ji Young Lee, Su Hyun Chae, and Chulmin Lee
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03 medical and health sciences ,030219 obstetrics & reproductive medicine ,0302 clinical medicine ,genetic structures ,Waste management ,business.industry ,digestive, oral, and skin physiology ,Medicine ,030212 general & internal medicine ,business - Abstract
Hot flush (hot flush or facial flush) is the most frequent symptom experienced by women of peri-menopausal age. It may appear on women or even men after surgery or chemotherapy. Hot flush is one of the biggest reason for women to undergo hormone replacement therapy (HRT). It also crucially affects various aspects of life quality such as occupation, social life, daily routine and health awareness. The most effective and fundamental remedy for hot flush is HRT. However, a few women is not responsive to HRT and investigation to elucidate other causes of hot flush is warranted, especially in elderly. The contraindications such as breast cancer mandates other modality of treatment. Variety of treatment for hot flush other than HRT will be discussed herein.
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- 2018
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26. High recovery and fouling resistant double stage seawater reverse osmosis: An inter-stage ERD configuration optimized with internally-stage design (ISD)
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Rusnang Syamsul Adha, Thanh-Tin Nguyen, Chulmin Lee, and In S. Kim
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Seawater reverse osmosis ,Energy recovery ,Materials science ,Fouling ,Mechanical Engineering ,General Chemical Engineering ,Analytical chemistry ,General Chemistry ,Permeation ,Dilution ,Membrane ,Deposition (phase transition) ,General Materials Science ,Stage (hydrology) ,Water Science and Technology - Abstract
Fouling in seawater reverse osmosis (SWRO) is a crucial parameter for a long-term operation. This study investigated a standard configuration wherein energy recovery device (ERD) being placed in the front of the first stage, an inter-stage ERD (ISERD) configuration wherein the ERD booster being placed in-between the two stages, and ISERDISD configuration wherein internally-staged design (ISD) being optimized by ISERD. The fouled ISERD-based configurations have been proven to sustain optimum permeate recovery to 55%–60%, produce permeate TDS of 397 mg/L (ISERD), and lower 378 mg/L (ISERDISD), better compared to 40–45% and TDS of 436 mg/L (standard one). Thanks to an improved flux distribution, the foulant deposition was halved to 11.7 in ISERD from 20.4 g/m2 and reduced further to the level of 10.3 g/m2 in ISERDISD. The ISERD exhibited almost the same apparent SEC as that of standard one (3.34 vs 3.26 kWh/m3), while ISERDISD exhibited reduced level to 2.75 kWh/m3. The incorporation of the fouling into the unit water cost (UWC) showed ISERDISD being the least costly with $0.45/m3 compared to $0.47 and $0.59/m3 for the ISERD and standard configurations respectively. An ultra-high-pressure membrane, osmotic dilution, and antiscalants for the loaded second stage might be recommended for ISERDISD implementation.
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- 2022
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27. Osmotic membrane under spacer-induced mechanical compression: Performance evaluation and 3D mechanical simulation for module optimization
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Chulmin Lee and In S. Kim
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Materials science ,Critical stress ,Stress–strain curve ,Structural integrity ,Filtration and Separation ,Biochemistry ,Finite element method ,Membrane ,Sphere packing ,Compression ratio ,Mechanical compression ,General Materials Science ,Physical and Theoretical Chemistry ,Composite material - Abstract
Osmotically-driven membrane process (ODMP), the low energy process that has attracted significant attention recently, has a relatively short history of development and there is a large room for improvement in membrane module design. Especially, it is significant but neglected how much membrane area should be packed into the module housing without undermining structural integrity and performance of the membrane. In this regard, this study aims to experimentally investigate the variation of osmotic membrane performance under varying spacer-induced mechanical compression and determine the critical compression ratio. 3D FEM (Finite element method) mechanical stimulation was employed to analyze the variation of stress and strain of membrane under mechanical compression and critical stress and strain were determined based on the experimental results. The study found that the performance of commercial osmotic membrane did not decrease significantly up to 30–40% of compression ratio and 45.5%–69.6% of the packing density of spiral-wound membrane module can be saved. The findings and methods suggested in this study will facilitate the structural optimization of ODMP membrane modules. Also, the discrepancy of the membrane performance between the lab-scale experiment (non-compressed) and commercial-scale membrane module (compressed) validated in this study emphasizes the importance of caution in the reporting of membrane performance.
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- 2022
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28. Corrigendum to 'Quantifying the influence of divalent cations mass transport on critical flux and organic fouling mechanism of forward osmosis membrane' [Desalination 512 (2021) 115146]
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Rusnang Syamsul Adha, Thanh-Tin Nguyen, In S. Kim, Dong-Ho Kim, and Chulmin Lee
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chemistry.chemical_classification ,Mass transport ,Fouling ,Chemistry ,Mechanical Engineering ,General Chemical Engineering ,Forward osmosis ,General Chemistry ,Desalination ,Divalent ,Membrane ,Chemical engineering ,General Materials Science ,Flux (metabolism) ,Mechanism (sociology) ,Water Science and Technology - Published
- 2021
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29. Comparison of hydrodynamics by backwashing and channel washing within hollow fiber membrane module using computational fluid dynamics
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Changkyoo Choi, Chulmin Lee, and In S. Kim
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Materials science ,business.industry ,Hollow fiber membrane ,Backwashing ,Mechanics ,Computational fluid dynamics ,business ,Communication channel - Published
- 2018
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30. Quantifying the influence of divalent cations mass transport on critical flux and organic fouling mechanism of forward osmosis membrane
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In S. Kim, Dong-Ho Kim, Chulmin Lee, Rusnang Syamsul Adha, and Thanh-Tin Nguyen
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chemistry.chemical_classification ,Aqueous solution ,Fouling ,Mechanical Engineering ,General Chemical Engineering ,Forward osmosis ,02 engineering and technology ,General Chemistry ,021001 nanoscience & nanotechnology ,Critical value ,Divalent ,Membrane ,Brine ,020401 chemical engineering ,Chemical engineering ,chemistry ,General Materials Science ,0204 chemical engineering ,0210 nano-technology ,Flux (metabolism) ,Water Science and Technology - Abstract
Understanding the insightful impact of divalent cations mass transport on the complex organic fouling of forward osmosis (FO) membrane is vital when seawater/brine is utilized in a FO hybrid process. Our works deeply focused on quantifying the influence of divalent cations on not only critical flux but also the organic fouling mechanism. The presence of divalent cations in aqueous solutions caused a decrease in critical flux values. The fouling mechanism is mainly governed by intermolecular and ion-mediated interactions. The findings suggested the interaction of divalent cations with organic matters close to the membrane surface is more noticeable than that in the feed solution. These interactions combined with an operation at the flux ≥30 LMH led to the formation of a compact and cohesive cake layer (4.8–9.1 μm) where the great divalent cations were deposited on membrane surface after 30 h operation (Ca2+: 162.13–256.72 g/m2, Mg2+: 182.60–374.38 g/m2). In contrast, 21 LMH below critical value exhibited minor fouling with a very thin cake layer (0.5 μm) and minimized deposited divalent cations (Ca2+: 79.47 g/m2, Mg2+: 46.65 g/m2). Overall, the extended operation of 30 h suggested 16–21 LMH were threshold values for FO fouling control.
- Published
- 2021
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31. Effect of intermittent pressure-assisted forward osmosis (I-PAFO) on organic fouling
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In S. Kim, Jinwoo Lee, Chulmin Lee, and Seungho Kook
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Fouling mitigation ,Fouling ,Chemistry ,Mechanical Engineering ,General Chemical Engineering ,Membrane fouling ,Forward osmosis ,Compaction ,Environmental engineering ,Flux ,02 engineering and technology ,General Chemistry ,Energy consumption ,021001 nanoscience & nanotechnology ,Membrane ,020401 chemical engineering ,General Materials Science ,0204 chemical engineering ,0210 nano-technology ,Water Science and Technology - Abstract
This study investigated the feasibility of intermittent pressure-assisted forward osmosis (I-PAFO) operation for organic fouling mitigation, using sodium alginate as the model foulant. FO and PAFO were also operated to compare system performances in terms of water flux behavior, flux recovery by physical cleaning, fouling propensity, energy consumption, and membrane area required. Results showed that I-PAFO obtained higher water flux and flux recovery by physical cleaning than PAFO because of its lower fouling tendency. I-PAFO was able to reduce not only the accumulated foulant mass on the membrane surface, but also fouling layer compaction through the intermittent pressurization. Furthermore, it displayed benefits in terms of reducing membrane area required and operating energy compared to PAFO, due to its higher water productivity and sustainability. Therefore, I-PAFO can be a plausible option for saving membrane costs and operating energy when FO operations are concerned particularly in accordance with hybridization with RO (i.e. I-PAFO-RO hybrid process).
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- 2017
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32. Comparison of laparoscopic and abdominal radical hysterectomy in early stage cervical cancer patients without adjuvant treatment: Ancillary analysis of a Korean Gynecologic Oncology Group Study (KGOG 1028)
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E Sun Paik, Chel Hun Choi, Jong Min Lee, Dong Hoon Suh, Yun Hwan Kim, Seok Ju Seong, Chulmin Lee, Eun Seop Song, Myong Cheol Lim, and Moon Hong Kim
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Adult ,medicine.medical_specialty ,medicine.medical_treatment ,Uterine Cervical Neoplasms ,Gynecologic oncology ,Kaplan-Meier Estimate ,Hysterectomy ,Disease-Free Survival ,Cohort Studies ,medicine ,Humans ,Stage (cooking) ,Radical Hysterectomy ,Laparoscopy ,Neoplasm Staging ,Retrospective Studies ,Cervical cancer ,medicine.diagnostic_test ,business.industry ,Obstetrics and Gynecology ,Middle Aged ,medicine.disease ,Surgery ,Survival Rate ,Oncology ,Propensity score matching ,Cohort ,Female ,Neoplasm Recurrence, Local ,business ,Adjuvant - Abstract
We compared two groups of early stage cervical cancer patients treated with different surgical methods without adjuvant treatment using retrospective multicenter data previously collected for Korean Gynecologic Oncology Group (KGOG) study designed for developing prognostic models.We initially assessed data from the multi-institutional cohort with early stage (IB-IIA) cervical cancer patients treated with radical hysterectomy without adjuvant treatment between 2000 and 2008. Propensity score matching was performed to compare disease-free survival (DFS) and overall survival (OS) of patients with laparoscopic to abdominal radical hysterectomy. Additionally, survival comparison was performed in patients with tumor size2 cm.After matching, 119 patients with laparoscopic radical hysterectomy were compared with 357 patients with abdominal radical hysterectomy (median follow-up of 63.9 months). Inferior DFS was observed in the laparoscopy group (HR 2.738 [95% CI 1.326-5.650], p = 0.005) with a significant difference in pelvic (HR 5.110 [95% CI 1.817-14.473], p 0.001) and hematogenous recurrence (HR 3.171 [95% CI 1.059-9.494], p = 0.03), but OS was not significantly different between two groups (p = 0.624). In subgroup analysis in the patient with tumor size2 cm (laparoscopy 62 vs. laparotomy 186, median follow-up of 69.1 months), laparoscopy was associated with lower rate of DFS (HR 12.987 [95% CI 1.451-116.244], p = 0.003), but no significant difference in OS was observed between groups. Regarding OS, number of events is lacking, and inferior DFS in the laparoscopy group may be compensated by better response to radiation therapy in pelvic recurrence.In this analysis, laparoscopic radical hysterectomy was associated with lower rates of DFS but not OS in early stage cervical cancer patients without adjuvant treatment. Further larger scale studies are needed.
- Published
- 2019
33. Critical flux-based membrane fouling control of forward osmosis: behavior, sustainability, and reversibility
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Chulmin Lee, Seungho Kook, Thanh-Tin Nguyen, Robert W. Field, and In S. Kim
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Materials science ,Fouling ,Colloidal silica ,Forward osmosis ,Membrane fouling ,F200 ,H900 ,Filtration and Separation ,H800 ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Biochemistry ,C900 ,0104 chemical sciences ,Cellulose triacetate ,chemistry.chemical_compound ,Flux (metallurgy) ,Membrane ,chemistry ,Chemical engineering ,General Materials Science ,Physical and Theoretical Chemistry ,0210 nano-technology - Abstract
Membrane fouling is closely related to the concept of critical flux. Therefore, a fouling control strategy for forward osmosis (FO) membranes that is based on the critical flux is necessary. This study systematically investigated the critical flux behavior of FO membranes (CTA and PA-TFC) in the short-term using a stepping method (draw solution (DS) concentration stepping). In addition, to test the reliability of this method, long-term experiments were conducted to evaluate the influences of operational critical flux on the fouling behavior (sustainable operation and fouling reversibility/irreversibility), thereby determining the critical flux for reversibility. Our results showed that the DS concentration stepping could be applied for critical flux determination in FO. Both membranes exhibited higher critical flux values for alginate fouling compared to other single foulants such as colloidal silica or gypsum. The values were 15.9 LMH for a cellulose triacetate membrane (CTA) and 20.5 LMH for the polyamide thin-film composite (PA-TFC). Whilst these values should be adequate in FO applications they were determined for single foulants. The presence of multispecies of foulants caused a significant decline in the critical flux values. This study found 5.4 LMH for the CTA membrane and 8.3 LMH for the PA-TFC membrane for the combined foulants of alginate + gypsum. This indicates that the critical flux behavior in FO was dependent on the foulant type and membrane type. Importantly, the high restoration of water flux was achieved with the PA-TFC membrane at an operation either close to critical flux (92–98%) or below critical flux (98–100%) (i.e., with negligible irreversible fouling). The critical fluxes for reversibility obtained in this study will aid the efficient operation of practical FO processes.
- Published
- 2019
34. An improved perm-selectivity prediction of forward osmosis membrane by incorporating the effect of the surface charge on the solute partitioning
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Chulmin Lee, Rusnang Syamsul Adha, Thanh-Tin Nguyen, Jaewon Jang, and In S. Kim
- Subjects
Mass transfer coefficient ,Membrane potential ,Materials science ,Diffusion ,Forward osmosis ,Thermodynamics ,Filtration and Separation ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Biochemistry ,0104 chemical sciences ,Cellulose triacetate ,chemistry.chemical_compound ,Membrane ,chemistry ,Mass transfer ,General Materials Science ,Surface charge ,Physical and Theoretical Chemistry ,0210 nano-technology - Abstract
Perm-selectivity consisting of water flux Jw and solute flux Js or in form of Js/Jw ratio is an important parameter of designing Forward Osmosis (FO) membrane as it indicates the membrane performance and how much solute replenishment over the extracted pure water from the feed solution. Parameter Js/Jw ratio is dependent on hydrodynamic condition i.e cross-flow velocity (CFV), solute type i.e. diffusivity, trans-membrane surface potential. This study employed Cellulose Triacetate (CTA) membrane for representing low-charge membrane and Polyamide-Thin Film Composite (PA-TFC) for the membrane of highly negative surface charge. Six (6) different models were used to quantify the effect of external mass transfer, the ideal solution, non-ideal solution, trans-membrane surface potential on the transport of solute across the membrane. Our new model was proven to improve the prediction of perm-selectivity. The improvement was attributed to the application of trans-membrane potential-dependent solute partitioning for solute permeability correction and the application of experimentally obtained mass transfer coefficient. By the incorporation of the Donnan effect in determining the transmembrane potential, it was found that in the low charge membrane namely CTA, the dominant transport mechanism was diffusion, while in a highly negative surface charged membrane namely TFC, the partition of solute to be the dominant mechanism. Operation at a low CFV posed less impact of the membrane charge. The newly developed model provided a good foundation for FO process design under different CFVs and modified surface charges.
- Published
- 2021
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35. Attitudes Toward Transgender People Among Medical Students in South Korea
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Chulmin Lee, Sa Ra Lee, Mun Nyeong Choi, Jaehyun Cho, Min-A Kim, Eun Sil Lee, and Suyeon Park
- Subjects
Urology ,Endocrinology, Diabetes and Metabolism ,education ,030232 urology & nephrology ,Psychological intervention ,lcsh:Medicine ,Dermatology ,Education ,03 medical and health sciences ,Behavioral Neuroscience ,0302 clinical medicine ,Endocrinology ,Transgender ,Attitudes Toward Transgendered Individuals Scale ,Original Research ,030219 obstetrics & reproductive medicine ,lcsh:R ,Genderism ,lcsh:Other systems of medicine ,lcsh:RZ201-999 ,Transgenderism ,Sexual minority ,Psychiatry and Mental health ,Reproductive Medicine ,Attitudes ,Genderism and Transphobia Scale ,Attitude change ,Lesbian ,Psychology ,Transphobia ,Clinical psychology - Abstract
Introduction Interventions aimed at changing knowledge, attitudes, and beliefs of resident physicians and medical students have been made to incite a significant positive increase in attitudes, comfort, and knowledge toward the lesbian, gay, bisexual, and transgender (LGBT) community, as well as increased levels of competency among participants. Aim To use insights from the attitudes of medical students toward transgender people and demonstrate that adding lectures on transgenderism would make the medical school curricula more comprehensive and trans-inclusive by improving overall attitudes toward the LGBT community. Methods A total of 49 medical students completed the preintervention survey with the Genderism and Transphobia Scale and Attitudes Toward Transgendered Individuals Scale, and then took a class on transgenderism, whereas 39 individuals completed the 4-week postintervention survey following the same measures. Main Outcome Measure Three items of survey were demographic characteristics, the Genderism and Transphobia Scale, and the Attitude Toward Transgender Individuals Scale. Results Although there was no significant difference in mean score between the preintervention and postintervention surveys, those who had minority individuals as peers and those who had previous LGBT-related education showed significantly positive attitudes than those without after the lecture. As a result of analyzing all the data from the pre/postintervention surveys, being of the female gender and having minority individuals as peers positively affected attitude. Conclusion Although there was no significant attitude change after the lecture, those who had previous LGBT-related education showed significantly positive attitudes at pre/postintervention surveys than those without. These findings suggest that raising awareness and education should be continued for a positive attitude toward more vulnerable groups such as the LGBT. Given the lack of studies on transgenderism that involve students in the medical profession in South Korea, this study shows the necessity of curricula creation of transgenderism education. This study aims to serve as a basis for curricula creation and student guidance that will help creating more positive attitudes toward sexual and gender minorities.
- Published
- 2020
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36. Transport analysis of particulate matter in media-saturated mesh tube filter for the desalination primary pretreatment process
- Author
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In S. Kim, Changkyoo Choi, Dong-Ho Kim, Sang-Jun Ahn, and Chulmin Lee
- Subjects
Roughing filter ,Suspended solids ,Range (particle radiation) ,Materials science ,Mechanical Engineering ,General Chemical Engineering ,Artificial seawater ,02 engineering and technology ,General Chemistry ,021001 nanoscience & nanotechnology ,law.invention ,020401 chemical engineering ,Chemical engineering ,law ,Particle ,General Materials Science ,Seawater ,0204 chemical engineering ,0210 nano-technology ,Porous medium ,Filtration ,Water Science and Technology - Abstract
Roughing filters (coarse media filtration) are a type of porous media filters used as pretreatment systems when the raw water contains a large amount of suspended particles and organic matter. Mesh tube filter media, roughing filter media composed of LDPE, are used in the process of removing suspended particles in wastewater treatment. In this study, we investigated the transport of suspended solids in saturated mesh tube filter media using kaolin particles (sizes range: 0.5–40 μm) and spherical SiO2 particles with particle sizes of 1.5, 10.4, and 19.5 μm. The results showed that the mesh tube filter media effectively removed suspended particles at sizes of 1–20 μm, and the removal rate of suspended particles under artificial seawater conditions was 5–50% higher than under freshwater conditions. It was also found that mechanism of removal of suspended particles varies with the velocity of the fluid by mass balance analysis. With high ion concentrations in the seawater conditions, the size of the suspended particles increased by 5–20%, which caused the suspended particles to be more strongly affected by gravity. The DLVO interaction energy analysis showed that the electrical attraction between suspended particles and filter media increased strongly in artificial seawater conditions.
- Published
- 2020
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37. Spatial and Temporal Exposure Assessment to PM2.5 in a Community Using Sensor-Based Air Monitoring Instruments and Dynamic Population Distributions
- Author
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SungChul Seo, Mansu Cho, Jeong-Il Lee, Hunjoo Lee, Wondeuk Jo, Chulmin Lee, Wonho Yang, and Jinhyeon Park
- Subjects
Atmospheric Science ,010504 meteorology & atmospheric sciences ,Population ,dynamic population distribution ,time–activity pattern ,lcsh:QC851-999 ,010501 environmental sciences ,Environmental Science (miscellaneous) ,complex mixtures ,01 natural sciences ,Concentration ratio ,Air monitoring ,Statistics ,education ,Beta attenuation monitoring ,0105 earth and related environmental sciences ,Exposure assessment ,education.field_of_study ,population exposure ,Network data ,Dynamic population ,exposure surveillance system ,fine particulate matter ,Environmental science ,lcsh:Meteorology. Climatology ,Population exposure - Abstract
This research was to conduct a pilot study for two consecutive days in order to assess fine particulate matter (PM2.5) exposure of an entire population in a community. We aimed to construct a surveillance system by analyzing the observed spatio-temporal variation of exposure. Guro-gu in Seoul, South Korea, was divided into 2,204 scale grids of 100 m each. Hourly exposure concentrations of PM2.5 were modeled by the inverse distance weighted method, using 24 sensor-based air monitoring instruments and the indoor-to-outdoor concentration ratio. Population distribution was assessed using mobile phone network data and indoor residential rates, according to sex and age over time. Exposure concentration, population distribution, and population exposure were visualized to present spatio-temporal variation. The PM2.5 exposure of the entire population of Guro-gu was calculated by population-weighted average exposure concentration. The average concentration of outdoor PM2.5 was 42.1 µ, g/m3, which was lower than the value of the beta attenuation monitor measured by fixed monitoring station. Indoor concentration was estimated using an indoor-to-outdoor PM2.5 concentration ratio of 0.747. The population-weighted average exposure concentration of PM2.5 was 32.4 µ, g/m3. Thirty-one percent of the population exceeded the Korean Atmospheric Environmental Standard for PM2.5 over a 24 h average period. The results of this study can be used in a long-term aggregate and cumulative PM2.5 exposure assessment, and as a basis for policy decisions on public health management among policymakers and stakeholders.
- Published
- 2020
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38. A comprehensive review of the feasibility of pressure retarded osmosis: Recent technological advances and industrial efforts towards commercialization
- Author
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In S. Kim, Suhun Kim, Joon Ha Kim, Eunmok Yang, Sung Ho Chae, and Chulmin Lee
- Subjects
Design modification ,Seawater reverse osmosis ,Computer science ,Mechanical Engineering ,General Chemical Engineering ,Pressure-retarded osmosis ,02 engineering and technology ,General Chemistry ,021001 nanoscience & nanotechnology ,Commercialization ,020401 chemical engineering ,General Materials Science ,Biochemical engineering ,0204 chemical engineering ,0210 nano-technology ,Implementation ,High potential ,Simulation methods ,Water Science and Technology - Abstract
Since the early 2000s, pressure retarded osmosis (PRO) has been continuously investigated, based on its potential to harvest energy from a salinity gradient. However, recent negative reports on its fundamental feasibility and the closure of the largest industrial implementation have slowed its momentum, with regard to its commercialization. In this respect, this review provides insights into the current status of PRO technologies in membrane fabrication, module design, process optimization, and industrial movements for the commercialization of PRO. Notably, despite dramatic advancements in lab-scale PRO membrane performance, recent modeling studies have revealed advanced membrane properties have only a minor impact on PRO performance. In contrast, developing PRO module designs are deemed to have paramount importance, due to the drastically low module performance compared to lab-scale membrane performance, and high potential of design modification to resolve inefficient PRO module structures. Various simulation methods for optimizing PRO processes using the classic mass transfer model, thermodynamics, and machine learning optimizations are comparatively analyzed. Integrations of seawater reverse osmosis and PRO and other hybrid processes with PRO are discussed in terms of recent pilot-scale implementations and modeling results. Finally, small and large industrial movements and projects for PRO commercialization are analyzed in detail, based on their quantitative outcomes.
- Published
- 2020
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39. Influence of hydrodynamic operating conditions on organic fouling of spiral-wound forward osmosis membranes: Fouling-induced performance deterioration in FO-RO hybrid system
- Author
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Rusnang Syamsul Adha, Ho Kyong Shon, Thanh-Tin Nguyen, In S. Kim, and Chulmin Lee
- Subjects
Osmosis ,Environmental Engineering ,Continuous operation ,0208 environmental biotechnology ,Forward osmosis ,02 engineering and technology ,Wastewater ,010501 environmental sciences ,01 natural sciences ,Water Purification ,Waste Management and Disposal ,0105 earth and related environmental sciences ,Water Science and Technology ,Civil and Structural Engineering ,Pressure drop ,Fouling ,Ecological Modeling ,Membrane fouling ,Environmental engineering ,Membranes, Artificial ,Pollution ,020801 environmental engineering ,Hydrodynamics ,Environmental science ,Seawater ,Filtration - Abstract
The forward osmosis-reverse osmosis (FO-RO) hybrid process has been extensively researched as part of attempts to reduce the high energy consumption of conventional seawater reverse osmosis in recent years. FO operating conditions play a substantial role in the hybrid process, dictating not only the performance of the entire system but also the propensity for fouling, which deteriorates performance in long-term field operations. Therefore, determining the optimal FO operating conditions with regard to membrane fouling may promote sustainable operation through efficient fouling control. This study thus evaluated the influence of each hydrodynamic operating condition (feed flowrate, draw flowrate, and hydraulic pressure difference) and their synergistic effects on fouling propensity in a pilot-scale FO operation under seawater and municipal wastewater conditions. Fouling-induced variation in water flux, channel pressure drop, diluted concentration, and the resulting specific energy consumption (SEC) were comparatively analyzed and utilized to project performance variation in a full-scale FO-RO system. Fouling-induced performance reduction significantly varied depending on hydrodynamic operating conditions and the resultant fouling propensity during 15 days of continuous operation. A high feed flowrate demonstrated a clear ability to mitigate fouling-induced performance deterioration in all conditions. A high draw flowrate turned out to be detrimental for fouling propensity since its high reverse solute flux accelerated fouling growth. Applying additional hydraulic pressure during FO operation caused a faster reduction of water flux, and thus feed recovery and water production; however, these drawbacks could be compensated for by a 10% reduction in the required FO membrane area and an additional reduction in RO SEC.
- Published
- 2020
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40. Insight into organic fouling behavior in polyamide thin-film composite forward osmosis membrane: Critical flux and its impact on the economics of water reclamation
- Author
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Chulmin Lee, Robert W. Field, In S. Kim, and Thanh-Tin Nguyen
- Subjects
chemistry.chemical_classification ,Materials science ,Fouling ,Forward osmosis ,Filtration and Separation ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Biochemistry ,0104 chemical sciences ,Membrane ,Wastewater ,chemistry ,Chemical engineering ,Thin-film composite membrane ,Polyamide ,Zeta potential ,Humic acid ,General Materials Science ,Physical and Theoretical Chemistry ,0210 nano-technology - Abstract
A strategy of using critical fluxes to control organic fouling of polyamide thin film composite (PA-TFC) forward osmosis (FO) membranes during wastewater reclamation was developed for FO mode. This work was a comprehensive investigation with various organic foulants covering complex mixtures as well as single foulants. The foulants were alginate (ALG), Humic acid (HA), and Bovine Serum Albumin (BSA) and the study covered different concentration (40; 80; 120; 160 mg/L). Our results indicated that there was a single value of critical flux, 35 LMH for 160 mg/L and single foulant. However the presence of mixed foulants i.e., ALG + BSA, ALG + HA, HA + BSA, at an overall foulant concentration of 160 mg/L gave rise to foulant-foulant-membrane interactions that caused a significant decrease in critical flux values to 25–30 LMH. Using these results as a guide, long-term tests in which there was no fouling or negligible fouling were successfully implemented. Operating below critical flux maintains a sustainable operation with the characteristic of full reversibility, which is vital if chemical cleaning is to be minimized. Characterization of fouling around critical values was made through physico-chemical analyses including SEM, EEM, aggregate size, zeta potential, and FTIR. It was found that FO fouling became irreversible when operated at a flux ≥35 LMH for single foulants and fluxes of 25 LMH and 30 LMH for ALG + BSA and HA + BSA foulants respectively, being a foulant concentration of 160 mg/L; such conditions are favorable for the formation of the cohesive and compact cake layer. Economic assessments based on specific energy consumption facilitated the production of guidelines for practical design and operation.
- Published
- 2020
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41. Graphene oxide nanocomposite membrane cooperatively cross-linked by monomer and polymer overcoming the trade-off between flux and rejection in forward osmosis
- Author
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Jaewon Jang, Sang-Soo Chee, Woong Lee, Insu Park, In S. Kim, Chulmin Lee, Yesol Kang, Jun-ho Song, and Moon-Ho Ham
- Subjects
chemistry.chemical_classification ,Nanocomposite ,Materials science ,Graphene ,Forward osmosis ,Membrane structure ,Filtration and Separation ,02 engineering and technology ,Polymer ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Biochemistry ,0104 chemical sciences ,law.invention ,chemistry.chemical_compound ,Monomer ,Membrane ,chemistry ,Chemical engineering ,law ,Molecule ,General Materials Science ,Physical and Theoretical Chemistry ,0210 nano-technology - Abstract
A forward osmosis membrane consisting of graphene oxide (GO) nanosheets cooperatively cross-linked by ethylenediamine (EDA) molecule and poly(acrylic acid) (PAA) polymer chain is proposed. Desirable GO-based nanocomposite membrane must satisfy the conflicting requirements of high water flux and salt rejection simultaneously, which is yet to be achieved. In this study, the GO/EDA/PAA nanocomposite structure demonstrates that good water flux (52 LMH) and salt rejection (97%) can be achieved simultaneously by cooperatively employing the short monomer molecule EDA and the long PAA polymer chain within the channel region of the GO nanocomposite membrane structure. It is suggested that the membrane-wide network of hydrogen bonds between the GO nanosheets and the PAA chains aligned parallel to them is supplemented by anchoring carbon-nitrogen covalent bonds between GO and EDA molecules to form the nanocomposite structure. The nanocomposite structure resulting from the configurations of EDA molecules and PAA chains within the channel region provide an optimal condition for blocking hydrated salt ions while allowing the flow of water molecules. Also, it functions as a reinforcement of the membrane structure for the improved structural integrity.
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- 2020
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42. Serially connected forward osmosis membrane elements of pressure-assisted forward osmosis-reverse osmosis hybrid system: Process performance and economic analysis
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Chulmin Lee, Seungho Kook, Jangho Lee, Ho Kyong Shon, Thanh-Tin Nguyen, and In S. Kim
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Computer science ,business.industry ,Mechanical Engineering ,General Chemical Engineering ,Forward osmosis ,Process (computing) ,Serial port ,02 engineering and technology ,General Chemistry ,010501 environmental sciences ,Chemical Engineering ,01 natural sciences ,Membrane ,020401 chemical engineering ,Hybrid system ,Economic analysis ,General Materials Science ,0204 chemical engineering ,Process engineering ,business ,Reverse osmosis ,Economic potential ,0105 earth and related environmental sciences ,Water Science and Technology - Abstract
© 2018 Elsevier B.V. Due to the improved dilution of draw streams, employing pressure-assisted forward osmosis (PAFO) to the hybrid system of forward osmosis (FO) followed by reverse osmosis (RO) for seawater desalination has been expected to reduce the overall economics. However, replacing FO with PAFO causes an additional energy cost in the seawater dilution step which inevitably leads to a question that PAFO-RO hybrid is truly an economically beneficial option. More importantly, though serial connection of FO elements improves the dilution of initial draw water, this economic benefit is also compensated with the additional membrane. To rationalize its overall performance and economic benefit, thorough performance and economic evaluations were conducted based on actual pilot-scale PAFO operations for serial connection of up to three 8040 FO elements. The results showed the FO-RO hybrid is not an economically feasible option unless a significant unit FO element cost cut-down is guaranteed. Meanwhile, PAFO-RO showed benefits with regards to target RO recovery and unit FO element cost, particularly when two FO elements are serially connected (SE2). It was found that PAFO-RO, indeed, has higher economic potential than FO-RO. A graphical overlapping method suggested in this work can help determine optimal serial configuration and operating conditions of PAFO-RO.
- Published
- 2018
43. Forward Osmosis Membranes under Null-Pressure Condition: Do Hydraulic and Osmotic Pressures Have Identical Nature?
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Jangho Lee, Chulmin Lee, In S. Kim, Seungho Kook, Tony Fane, and Chivukula D. Swetha
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Osmosis ,Water transport ,Materials science ,Diffusion ,Forward osmosis ,Membranes, Artificial ,02 engineering and technology ,General Chemistry ,Mechanics ,010501 environmental sciences ,01 natural sciences ,Volumetric flow rate ,Water Purification ,Membrane ,020401 chemical engineering ,Osmotic Pressure ,Pressure ,Environmental Chemistry ,Osmotic pressure ,0204 chemical engineering ,Porous medium ,0105 earth and related environmental sciences - Abstract
Forward osmosis (FO) membranes fall into the category of nonporous membranes, based on the assumption that water and solute transport occur solely based on diffusion. The solution-diffusion (S-D) model has been widely used in predicting their performances in the coexistence of hydraulic and osmotic driving forces, a model that postulates the hydraulic and osmotic driving forces have identical nature. It was suggested, however, such membranes may have pores and mass transport could occur both by convection (i.e., volumetric flow) as well as by diffusion assuming that the dense active layer of the membranes is composed of a nonporous structure with defects which induce volumetric flow through the membranes. In addition, the positron annihilation technique has revealed that the active layers can involve relatively uniform porous structures. As such, the assumption of a nonporous active layer in association with hydraulic pressure is questionable. To validate this assumption, we have tested FO membranes under the conditions where hydraulic and osmotic pressures are equivalent yet in opposite directions for water transport, namely the null-pressure condition. We have also established a practically valid characterization method which quantifies the vulnerability of the FO membranes to hydraulic pressure.
- Published
- 2018
44. Carcinosarcoma of the uterine cervix arising from Müllerian ducts
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Hoon Choi, Guhyun Kang, Chulmin Lee, Kyoung-Chul Chun, Myounghwan Kim, and Ji-Kyung Ko
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Gynecology ,medicine.medical_specialty ,Pathology ,business.industry ,Mullerian Ducts ,Obstetrics and Gynecology ,Estrogen receptor ,Case Report ,Gynecologic Oncology ,Müllerian tumor mixed ,medicine.disease ,Cervix uteri ,Mesonephric duct ,Müllerian duct ,Carcinosarcoma ,medicine ,Cervical Carcinosarcoma ,Sarcoma ,Stage (cooking) ,Radical Hysterectomy ,Breast neoplasms ,business - Abstract
Carcinosarcomas of the uterine cervix are extremely rare. Cervical carcinosarcoma can be characterized by having two different origins: the Mullerian ducts and the mesonephric duct remnants. A 53-year-old Korean woman was admitted to the hospital because of pelvic mass detected on computed tomography scan done at private clinic. A Radical hysterectomy with bilateral salpingooophorectomy and pelvic lymphadenectomy was carried out upon a diagnosis of stage IB2 cervical sarcoma. Immunohistochemically, the epithelial component was positive for pancytokeratin and estrogen receptor, but negative for CD 10 and carletinin. The mesenchymal component was positive for vimentin. The histopathologic diagnosis was a carcinosarcoma of the uterine cervix arising from Mullerian ducts. She underwent chemotherapy. She developed systemic recurrence seven months after operation and died of disease. The origin of cervical carcinosarcoma needs to be verified and immunohistochemical studies using mesonephric marker (CD 10, carletinin, and estrogen receptor) is helpful.
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- 2015
45. A Comparison of Adenosquamous Carcinoma and Adenocarcinoma of the Cervix after Radical Hysterectomy
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Seo Kyung Hahn, Jae Weon Kim, Noh Hyun Park, Hee Seung Kim, Yong Sang Song, Chulmin Lee, Hyun Hoon Chung, and Jung Yun Lee
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Adult ,Oncology ,medicine.medical_specialty ,Adenosquamous carcinoma ,medicine.medical_treatment ,Uterine Cervical Neoplasms ,Adenocarcinoma ,Hysterectomy ,Gastroenterology ,Carcinoma, Adenosquamous ,Internal medicine ,medicine ,Carcinoma ,Humans ,Neoplasm Invasiveness ,Radical Hysterectomy ,Survival rate ,Aged ,Retrospective Studies ,Cervical cancer ,business.industry ,Obstetrics and Gynecology ,Chemoradiotherapy, Adjuvant ,Middle Aged ,Prognosis ,medicine.disease ,Survival Rate ,Treatment Outcome ,Reproductive Medicine ,Lymphatic Metastasis ,Female ,Neoplasm Recurrence, Local ,business ,Chemoradiotherapy - Abstract
Background/Aims: The aim of this study was to compare the survival outcomes of adenocarcinoma and adenosquamous carcinoma in early-stage cervical cancer patients after radical hysterectomy. Methods: A retrospective analysis was performed of stage IB-IIA cervical cancer patients with adenocarcinoma or adenosquamous carcinoma who underwent radical hysterectomy at Seoul National University Hospital between 1998 and 2008. Results: A total of 166 patients with adenosquamous carcinoma (ASC) (n = 38) and adenocarcinoma (AC) (n = 128) were identified. In terms of baseline characteristics, the ASC group had higher rates of lymph node metastasis, deep stromal invasion, and lymphovascular space invasion than the AC group. However, there was no significant difference between the two histological subtypes in terms of recurrence-free survival (p = 0.396) and overall survival (p = 0.223). Patients with ASC showed similar outcomes to those with AC when limiting to either an intermediate/high-risk group or patients who underwent adjuvant concurrent chemoradiotherapy. Conclusion: Although the ASC group presented poorer pathologic findings after radical hysterectomy compared with the AC group, there was no significant difference in survival outcomes. This suggests that intermediate/high-risk patients with ASC may be successfully treated with postoperative concurrent chemoradiotherapy.
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- 2015
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46. Corrigendum to 'Performance analysis of serially-connected membrane element for pressure-assisted forward osmosis: wastewater reuse and seawater desalination' published in vol. 183, April 2020, pp. 104-113 (doi:10.5004/dwt.2020.25260)
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Chulmin Lee, Rusnang Syamsul Adha, Nguyen Thanh Tin, and In S. Kim
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Membrane ,Wastewater reuse ,Seawater desalination ,Forward osmosis ,Environmental engineering ,Environmental science - Published
- 2020
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47. Prognosis of Adenosquamous Carcinoma Compared With Adenocarcinoma in Uterine Cervical Cancer: A Systematic Review and Meta-Analysis of Observational Studies
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Noh Hyun Park, Hyun Hoon Chung, Mi-Na Kim, Chulmin Lee, Jae Weon Kim, Jung Yun Lee, Yong Sang Song, Hee Seung Kim, and Seokyung Hahn
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Oncology ,Cervical cancer ,medicine.medical_specialty ,business.industry ,Adenosquamous carcinoma ,Uterine Cervical Neoplasms ,Obstetrics and Gynecology ,Adenocarcinoma ,Prognosis ,medicine.disease ,Confidence interval ,Carcinoma, Adenosquamous ,Observational Studies as Topic ,Text mining ,medicine.anatomical_structure ,Meta-analysis ,Internal medicine ,medicine ,Humans ,Female ,Observational study ,business ,Cervix - Abstract
ObjectiveThe aim of this study was to compare the survival outcomes of adenosquamous carcinoma (ASC) and adenocarcinoma (AC) of the cervix.MethodsWe searched PubMed and Embase for observational studies that compared the outcomes of 2 histologic subtypes. Hazards ratios (HRs) with 95% confidence intervals (CIs) were calculated with a fixed effects model.ResultsA total of 17 studies were included in the analyses. Patients with ASC were associated significantly with poorer overall survival (death HR, 1.27; 95% CI, 1.12–1.43; I2= 0%) and recurrence-free survival (recurrence HR, 1.43; 95% CI, 1.05–1.95; I2= 19.4%) than those with AC. For clinical stages I and II in particular, ASC predicted significantly poorer outcomes compared with AC (death HR, 1.41; 95% CI, 1.17–1.70; I2= 0%).ConclusionsThis meta-analysis suggests that ASC may have poorer outcomes compared with AC of the cervix.
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- 2014
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48. Modeling of flow uniformity by installing inlet distributor within the inflow part of a pressurized module using computational fluid dynamics.
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Changkyoo Choi, Chulmin Lee, and Kim, In S.
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ENERGY consumption ,NON-uniform flows (Fluid dynamics) ,DISTRIBUTION (Probability theory) ,WATER distribution ,FLOW velocity - Abstract
Uniform flow distribution is a significant parameter for designing pressurized membrane modules because non-uniform flow distribution can cause serious local flux and fouling problems within a module. Thus, this study investigated the fluid behavior with regards to the evenness of water distribution using newly designed inlet distributors in the inflow part of a pressurized membrane module. From the results of velocity and pressure at the cross-sectional and outlet planes, we confirmed that a conventional membrane module with no distributor (non-distributor) had fluid that was concentrated at the central part. Case 1, which had a cross-shaped distributor, reduced the central concentration tendency, and Case 2, which had a round-shaped distributor, displayed a relatively uniform flow based on the velocity, pressure, flux, and standard deviation data. Here, the non-uniformity coefficient (N) and energy utilization (η) for Cases 1 and 2 showed a lower non-uniformity coefficient (0.030 and 0.017, respectively) than for the Non-distributor (0.039). The energy utilization of Cases 1 and 2 were higher (1.35e-0.5 and 1.46e-05) than the Non-distributor (1.64e-05). Overall, we confirmed that the inlet distributors led to increased evenness of flow distribution within an inflow part. [ABSTRACT FROM AUTHOR]
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- 2020
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49. Numerical study of fluid behavior on protruding shapes within the inlet part of pressurized membrane module using computational fluid dynamics.
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Changkyoo Choi, Chulmin Lee, No-Suk Park, and Kim, In S.
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FLUID pressure ,FLUID flow ,REYNOLDS number ,INLETS ,STANDARD deviations - Abstract
This study analyzes the velocity and pressure incurred by protruding shapes installed within the inlet part of a pressurized membrane module during operation to determine the fluid flow distribution. In this paper, to find the flow distribution within a module, it investigates the velocity and pressure values at cross-sectional and outlet planes, and 9 sections classified on outlet plane using computational fluid dynamics. From the Reynolds number (Re), the fluid flow was estimated to be turbulent when the Re exceeded 4,000. In the vertical cross-sectional plane, shape 4 and 6 (round-type protrusion) showed the relatively high velocity of 0.535 m/s and 0.558 m/s, respectively, indicating a uniform flow distribution. From the velocity and pressure at the outlet, shape 4 also displayed a relatively uniform fluid velocity and pressure, indicating that fluid from the inlet rapidly and uniformly reached the outlet, however, from detailed data of velocity, pressure and flowrate obtained from 9 sections at the outlet, shape 6 revealed the low standard deviations for each section. Therefore, shape 6 was deemed to induce the ideal flow, since it maintained a uniform pressure, velocity and flowrate distribution. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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50. Effect of Spacer Configuration on the Characteristics of FO Membranes: Alteration of Permeation Characteristics by Membrane Deformation and Concentration Polarization.
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Chulmin Lee, Jaewon Jang, Nguyen Thanh Tin, Suhun Kim, Tang, Chuyang Y., and Kim, In S.
- Published
- 2020
- Full Text
- View/download PDF
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