Publications by authors named "Minkyu Choi"

This study evaluated denitrification systems using two carbon sources: glucose alone (G), and a mixture of glucose, methanol, and sodium acetate (GMS), treating synthetic saline wastewater to prove the superior operational efficiency of the mixed carbon sources. Both systems showed excellent nitrogen removal under 80 g-NaCl L, but the glucose-based system exhibited unstable nitrate removal at a low C/N ratio of 3. Microbial community composition was distinct between the systems.

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To determine the potentially detrimental impacts of short-chain chlorinated paraffins (SCCPs), we conducted assessments of acute effects on 96-h survival rate and biochemical markers, as well as chronic and multigenerational impacts on growth and reproduction over three generations in the marine mysid, Neomysis awatschensis. Dose-dependent increase of mortality was measured in both juvenile and adult mysids for 96 h. Exposure to the LC10 value (derived from the 96-h acute toxicity value) significantly reduced feeding activity in juveniles, accompanied by a significant elevation in oxidative stress and a reduction in acetylcholinesterase activity.

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Introduction: Gastrointestinal (GI) magnetic resonance imaging (MRI) enables simultaneous assessment of gastric peristalsis, emptying, and intestinal filling and transit. However, GI MRI in animals typically requires anesthesia, which complicates physiology and confounds interpretation and translation to humans. This study aimed to establish GI MRI in conscious rats, and for the first time, characterize GI motor functions in awake versus anesthetized conditions.

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Introduction: Gastrointestinal (GI) magnetic resonance imaging (MRI) can simultaneously capture gastric peristalsis, emptying, and intestinal filling and transit. Performing GI MRI with animals requires anesthesia, which complicates physiology and confounds interpretation and translation from animals to humans. This study aims to enable MRI in conscious rats, and for the first time, characterize GI motor functions in awake versus anesthetized conditions.

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Humans actively observe the visual surroundings by focusing on salient objects and ignoring trivial details. However, computer vision models based on convolutional neural networks (CNN) often analyze visual input all at once through a single feedforward pass. In this study, we designed a dual-stream vision model inspired by the human brain.

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The stomach's ability to store, mix, propel, and empty its content requires highly coordinated motor functions. However, current diagnostic tools cannot simultaneously assess these motor processes. This study aimed to use magnetic resonance imaging (MRI) to map multifaceted gastric motor functions, including accommodation, tonic and peristaltic contractions, and emptying, through a single noninvasive experiment for both humans and rats.

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Evogliptin (EV) is a novel dipeptidyl peptidase-4 inhibitor (DPP4i) for glycemic control in patients with type 2 diabetes mellitus (T2DM). This study evaluated the pharmacokinetic (PK) and pharmacodynamic (PD) interactions between EV and sodium glucose cotransporter-2 inhibitors (SGLT2i) in healthy volunteers since combination therapy of DPP4i and SGLT2i has been considered as an effective option for T2DM treatment. A randomized, open-label, multiple-dose, two-arm, three-period, three treatments, two-sequence crossover study was conducted in healthy Korean volunteers.

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Objective: Gastrointestinal magnetic resonance imaging (MRI) provides rich spatiotemporal data about the movement of the food inside the stomach, but does not directly report muscular activity on the stomach wall. Here we describe a novel approach to characterize the motility of the stomach wall that drives the volumetric changes of the ingesta.

Methods: A neural ordinary differential equation was optimized to model a diffeomorphic flow that ascribed the deformation of the stomach wall to a continuous biomechanical process.

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Semaglutide, one of the most potent glucagon-like peptide (GLP)-1 analogs, has widely been used to treat type II diabetes mellitus and obesity. Recent studies have shown that semaglutide also works on the brain, suggesting its potential utility for various diseases, including Parkinson's disease and Alzheimer's disease. This study aimed to develop a novel liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis of semaglutide in both plasma and brain to characterize the pharmacokinetics and brain distribution in rats.

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Resting state functional magnetic resonance imaging (rsfMRI) data exhibits complex but structured patterns. However, the underlying origins are unclear and entangled in rsfMRI data. Here we establish a variational auto-encoder, as a generative model trainable with unsupervised learning, to disentangle the unknown sources of rsfMRI activity.

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Concentrations of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) were measured in 23 seafood species widely consumed by the Korean population in the periods of 2005-2007, 2010-2011, and 2015-2017. The ΣPCB (sum of 82 PCB congeners) and ΣPBDE (sum of 19 PBDE congeners) concentrations in the seafood samples of 2015-2017 were 0.06-6.

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To improve stability of nitrogen removal in partial nitritation (PN)-anammox process, flat-type cryogel films using poly (vinylalcohol) named as FT-CPVAF were applied in continuous reactors. Stable PN operation was maintained with short acclimation of 8 days and ammonium oxidation rate of 1.68 ± 0.

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Concentrations of polychlorinated dibenzo-para-dioxins and dibenzofurans (PCDD/Fs) were measured in sediment and bivalves at 25 locations along the Korean coasts during 2001-2012. Concentrations of PCDD/Fs in sediment and bivalves ranged from 0.15 to 18.

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Arsenic contamination in marine environments is a serious issue because some arsenicals are very toxic, increasing the health risks associated with the consumption of marine products. This study describes the development of an improved rapid method for the quantification of arsenic species, including arsenite (As), arsenate (As), arsenocholine (AsC), arsenobetaine (AsB), dimethylarsinic acid (DMA), and monomethyl arsonic acid (MMA), in seaweed, sediment, and seawater samples using high-performance liquid chromatography/inductively coupled plasma-mass spectrometry (HPLC/ICP-MS). ICP-MS based on dynamic reaction cells was used to eliminate spectral interference.

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Background: Osteoporosis and osteopenia are characterized by reduced bone mineral density (BMD) and increased fracture risk. Although the risk of fractures is higher in underweight people than in overweight people, the accumulation of body fat (especially abdominal fat) can increase the risk of bone loss. This study aimed to evaluate the association between body fat percentage and BMD in normal-weight middle-aged Koreans.

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This study investigated the effect of seeding source on the mature anaerobic ammonia oxidation (ANAMMOX) bacterial community niche in continuous poly(vinyl alcohol) (PVA) gel systems operated under high nitrogen loading rate (NLR) condition. Four identical column reactors packed with PVA gels were operated for 182 d using different seeding sources which had distinct community structures. The ANAMMOX reaction was achieved in all the bioreactors with comparable total and ANAMMOX bacterial 16S rRNA gene quantities.

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In this study, anammox enrichment reactors were operated using flat type poly (vinyl alcohol) cryogel (cryoPVAG) with precultured anammox bacteria (PAB) and activated sludge (AS) from an anoxic tack of the A2O process to evaluate the effect of different seeding sources on anammox enrichment. In addition, cryoPVAGs with different thicknesses (1, 2, and 3 mm) were used to investigate the effects of the thickness on anammox enrichment. The regression analysis with a modified Gompertz model showed that the start-up period of the anammox enrichment using PAB inoculum was approximately 14 days earlier than that of AS inoculum at a nitrogen loading rate of approximately 1 kg-N m day.

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Objective: The early identification of predictors related to cardiovascular disease risk factor clustering (CVD-RFC) can help prevent chronic disease. We aimed to identify the risk factors for CVD-RFC in adolescents.

Methods: A prospective longitudinal cohort study design was used to obtain data included in these analyses from school-aged children who participated in the Korean Child-Adolescent Study 2008-2014.

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In this study, the effects of the ammonium loading rate (ALR) and inorganic carbon loading rate (ILR) on the nitrification performance and composition of a nitrifying bacterial community were investigated in a moving bed biofilm reactor, using poly(vinyl alcohol) (PVA) sponge cubes as a supporting carrier. Between the two ALRs of 0.36 and 2.

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Environmental contamination by siloxanes is a matter of concern due to their widespread consumption in personal care as well as industrial products and potential toxicity. Nevertheless, methods for simultaneous determination of cyclic and linear siloxanes in sediment are lacking. In this study, we developed an optimized analytical method to determine cyclic and linear siloxanes based on gas chromatography coupled to tandem mass spectrometry (GC-MS/MS).

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This letter proposes a novel predictive coding type neural network model, the predictive multiple spatiotemporal scales recurrent neural network (P-MSTRNN). The P-MSTRNN learns to predict visually perceived human whole-body cyclic movement patterns by exploiting multiscale spatiotemporal constraints imposed on network dynamics by using differently sized receptive fields as well as different time constant values for each layer. After learning, the network can imitate target movement patterns by inferring or recognizing corresponding intentions by means of the regression of prediction error.

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The process performance and microbial niche of anaerobic ammonia oxidation (ANAMMOX) bacteria were compared in two identical bioreactors inoculated with different inoculum sources (i.e., pre-cultured ANAMMOX bacteria: PAB and activated sludge: AS) entrapped in poly(vinyl alcohol)/sodium alginate (PVA/SA) gel beads for a long-term period (i.

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The concentrations of trace metals (As, Cd, Co, Cu, Fe, Hg, Pb, and Zn) were measured in muscle and hepatopancreas of two Chionoecetes crabs (Chionoecetes japonicus and C. opilio) caught from the East/Japan Sea (EJS) in order to assess the potential health risk by the consumption of deep sea crabs. The highest metal concentrations in muscle and hepatopancreas were As and Fe, respectively, while the lowest metal concentration in two tissues was Pb.

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Background: The gut microbiota has emerged as an important environmental factor associated with obesity, type 2 diabetes, and cardiovascular disease, through its interactions with dietary factors. Therefore, we analyzed the composition of the fecal microbiota and levels of biochemical markers related to metabolic disease according to dietary pattern in Korean adolescents.

Methods: We collected fecal samples from 112 student subjects aged 13-16 years with sufficient information available regarding clinical biomarkers and diet, and performed 16S rRNA targeted gene sequencing.

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