Publications by authors named "June-Seok Choi"

Urine dilution is often performed to avoid clogging or scaling of pipes, which occurs due to urine's Ca and Mg precipitating at the alkaline conditions created by ureolysis. The large salinity gradient between urine and flushing water is, theoretically, a source of potential energy which is currently unexploited. As such, this work explored the use of a compact reverse electrodialysis (RED) system to convert the chemical potential energy of urine dilution into electric energy.

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Background: Implant-based dual-plane augmentation mammoplasty requires accurate separation of the pectoralis major muscle (PMM) at its origins. The authors identified the PMM origins during breast reconstruction surgery with the goal of providing additional information on subpectoral implant insertion for reconstructive or aesthetic purposes.

Methods: This study was conducted on 67 patients who underwent breast reconstruction surgery at the breast center of our hospital between November 2016 and June 2018.

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Background: This study aimed to determine the magnitude of volume reduction of the latissimus dorsi (LD) muscle after treatment using only postoperative radiotherapy (PORTx) in patients who underwent immediate breast reconstruction using an extended LD musculocutaneous (eLDMC) flap after partial mastectomy.

Methods: We retrospectively reviewed 28 patients who underwent partial mastectomy and an eLDMC flap, received only PORTx, and underwent chest computed tomography (CT) 7 to 10 days after surgery and 18±4 months after the end of radiotherapy, from March 2011 to June 2016. The motor nerve to the LD was resected in all patients.

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Reverse osmosis (RO) is the most widely used technology in water treatment and desalination technologies for potable water production. Since its invention, RO has undergone significant developments in terms of material science, process, system optimization, methods of membrane synthesis, and modifications. Among various materials used for the synthesis of an RO membrane, the polyamide thin-film composite (PA-TFC) is by far the most common, owing to its excellent water permeability high salt rejection, and stability.

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Brine disposal is a major drawback for seawater desalination. Membrane distillation (MD) is an emerging technology to treat a high saline water including brine disposal instead of reverse osmosis, multi-stage flash and multi-effect distillation. This study investigated a pilot scale of a spiral-wound air gap MD (AGMD) module and evaluated its efficiency.

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Several defluoridation techniques for reducing high initial fluoride concentration (IFC) in wastewater have been tested, but only a few of them have achieved the permissible standards. This study examined the hybrid crystallization-reverse osmosis technique (HRO) in light of flux, fluoride removal efficiency, fouling tendency, mineral recovery, complying zero liquid discharge (ZLD), and effluent discharge standard (EDS). Simulated wastewater with an IFC of 6600 mg/L was utilized and the final HRO performance was compared with those of the low-pressure (30 bar) standalone reverse osmosis (SRO), nanofiltration (SNF), and membrane distillation (SMD) processes.

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Four commercially available hydrophobic membranes with different pore sizes were separately used in a direct contact membrane distillation (DCMD) apparatus to investigate the effect of fouling on the mass transfer coefficient, and the dominant mass transport mode under different conditions defined by the temperature, membrane material, flow regime, and membrane pore size. Both ultrapure deionized water and simulated industrial wastewater were considered as the feed water. The results of the investigation confirmed that the fouling layer impacted the mass transport directly by resisting it, and indirectly by altering the heat transfer mechanism.

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Background: Malignant melanoma is the most aggressive skin cancer, and metastatic malignant melanoma is very difficult to treat. Ginsenoside Rg3 extracted from ginseng has been reported to have anticancer effects in various kinds of cancer. It has also been reported that Rg3 induced apoptosis and inhibited metastasis of melanoma cells derived from rats, but studies on the anti-cancer effects of Rg3 on melanoma cells originating from humans have been rarely reported.

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Background: Dermoid cysts are congenital tumors that are benign. Dermoid cysts with intracranial extension can cause serious neurological complications. It is important, therefore, to determine whether a patient has a dermoid cyst when their chief concern at a doctor's visit is a mass in the head or neck area.

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The effects of bioreactor temperatures and salinities of an anaerobic membrane distillation bioreactor (anMDBR) on the permeation performance and their potential recovery of bioresources were fully examined in this study. To the best of our knowledge, this is the first study of a lab-scale anMDBR process utilizing sub-merged hollow fiber membranes. The hybrid system utilizing both membrane distillation (MD) and anaerobic bioreactors achieved 99.

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A schwannoma is a benign tumor that develops from Schwann cells. It is known to occur more frequently in women than men, and about one third of schwannoma cases occur in the head and neck area. It is also known to originate mainly in the auditory nerve.

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Substantial amounts of trace hazardous elements have been detected in industrial wastewater (e.g fluoride > 900 mg/L). Feed water characteristics, operational parameters, and membrane properties are major factors affecting flux and rejection of the MD process.

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Background: Forehead flaps are useful for facial reconstruction. Studies of these flaps have mostly focused on the results of the reconstruction. However, due to the scarring and changes on the forehead caused by the median forehead flap (MFF), surgeons may be reluctant to perform this flap.

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Intraosseous hemangioma is an extremely rare tumor that accounts for 1% or fewer of all osseous tumors. The most common sites of its occurrence are the vertebral column and calvaria. Occurrence in a facial bone is very rare.

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In this study, composite membranes were fabricated via layer-by-layer (LBL) assembly of negatively charged silica aerogel (SiA) and 1H,1H,2H,2H-perfluorodecyltriethoxysilane (FTCS) on a polyvinylidene fluoride phase inversion membrane and interconnecting them with positively charged poly(diallyldimethylammonium chloride) (PDDA) via electrostatic interaction. The results showed that the PDDA-SiA-FTCS coated membrane had significantly enhanced the membrane structure and properties. New trifluoromethyl and tetrafluoroethylene bonds appeared at the surface of the coated membrane, which led to lower surface free energy of the composite membrane.

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Background: Free-flap surgery and skin grafting can be used to reconstruct large facial defects that may result after skin cancer removal by Mohs micrographic surgery (MMS). However, these two methods may produce low postsurgical patient satisfaction with aesthetics, and free-flap surgery may produce an undue burden for the majority of skin cancer patients, who are of advanced age. Hence, the authors examined outcomes of large facial defect reconstruction using multiple flaps.

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A pilot-scale pressured hollow-fiber microfiltration (MF) process as pretreatment for the reverse osmosis process was studied and operated under various conditions to assess the relative influence of backwashing, chemical enhanced backwashing (CEB), and bag filter application. The pilot plant process consisted of backwashing but without the CEB or the bag filter as the first step of the research. As the second step of the research, the impact of the backwashing on permeability recovery was assessed at different intervals followed by the influence of CEB on flowrate recovery.

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An economic desalination system with a small scale and footprint for remote areas, which have a limited and inadequate water supply, insufficient water treatment and low infrastructure, is strongly demanded in the desalination markets. Here, a direct contact membrane distillation (DCMD) process has the simplest configuration and potentially the highest permeate flux among all of the possible MD processes. This process can also be easily instituted in a multi-stage manner for enhanced compactness, productivity, versatility and cost-effectiveness.

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