Publications by authors named "Youngbo Sim"

Background And Purpose: Tinnitus is a condition in which individuals perceive sounds, such as ringing or buzzing, without any external source. Although the exact cause is not fully understood, recent studies have indicated the involvement of nonauditory brain structures, including the limbic system. We aimed to compare the volumes of specific brain structures between patients with tinnitus and controls.

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Article Synopsis
  • The study explored how a conductive biofilm supporter affects biohydrogen production in two types of dynamic membrane bioreactors (DMBRs), one with a nonconductive and the other with a conductive mesh.
  • DMBR with conductive stainless-steel mesh (DMBR II) showed a 16.8% increase in hydrogen productivity compared to the nonconductive version, alongside higher NADH/NAD ratios and lower oxidation-reduction potential (ORP).
  • Analysis indicated that the conductive mesh favored hydrogen-producing pathways while suppressing competitive processes, with electroactive Clostridium sp. identified as dominant hydrogen producers in the DMBR II.
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This study aimed to mitigate the instability in the start-up and continuous performance of dark fermentative biohydrogen production using heat-treated sludge by the addition of an exogenous H-producing strain. Continuous fermentation augmented with Clostridium butyricum showed the highest average biohydrogen production rate (HPR) as 50.35 ± 2.

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This study examined a two-stage dynamic membrane bioreactor (DMBR) system for biohydrogen and biomethane production from food waste (FW) in mesophilic condition. The two-stage DMBR system enabled high-rate H and CH production from particulate feedstock by enhanced microorganism retention. Chemical energy in FW was recovered up to 79% as renewable energy.

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This study aimed a high-rate dark fermentative H production from xylose using a dynamic membrane module bioreactor (DMBR) with a 444-μm pore polyester mesh. 20 g xylose/L was fed continuously to the DMBR at different hydraulic retention times (HRTs) from 12 to 3 h at 37 °C. The maximum average H yield (HY) and H production rate (HPR) at 3 h HRT were found to be 1.

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This study examined the effect of various inocula on mixed-culture dark fermentative H production from food waste. Heat-treated and frozen H-producing granular sludge (HPG) grown with monomeric sugars showed a higher H yield, production rate, and acidogenic efficiency along with a shorter lag phase than heat-treated methanogenic sludge. Among three different methods of methanogenic sludge inoculation, inoculation after centrifugation showed better H production performance.

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This study aimed to achieve continuous biohydrogen production from red algal biomass using a dynamic membrane bioreactor (DMBR). The DMBR was continuously fed with pretreated Echeuma spinosum containing 20 g/L hexose. The highest average hydrogen production rate (HPR) of 21.

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This study examined the feasibility of dark fermentative biohydrogen production from food waste using hybrid immobilization in mesophilic condition. Among four different organic loading rates (OLRs), the highest average hydrogen production rate (HPR) of 9.82 ± 0.

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This study examined the effect of shear velocity on biohydrogen producing dynamic membrane bioreactor (DMBR) containing 50 µm polyester mesh as supporting material. Increase of shear velocity up to 6.75 m/h enhanced hydrogen production performance as well as biomass retention in both suspended and attached forms, while wash-out was found at a shear velocity of 11.

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Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease. However, no reliable biomarkers have been identified to represent the clinical status. This study aimed to investigate whether diffusion tensor imaging (DTI) findings are useful imaging biomarkers to indicate the clinical status of ALS patients.

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Several studies used automated segmentation of hippocampal subfield (ASHS) for detailed measurements of anatomic subregions of the hippocampus, especially in the field of neurodegenerative disorders. In this study, we investigated the hippocampal subfield volume of patients with early-stage nondementia PD compared with normal healthy subjects using the ASHS method. A total of 32 subjects were enrolled in this study (sixteen patients with drug naive nondementia PD and sixteen healthy controls).

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This study aimed to investigate the relationship among dynamic membrane (DM) formation, metabolic flux, and microbial community population in dark fermentative hydrogen production. A continuously stirred tank reactor was equipped with an external submerged polyester screen mesh and inoculated with heat-treated anaerobic sludge without immobilization. DM was successfully developed on the polyester mesh and provided high-rate hydrogen production at 60.

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This study investigated the kinetic parameters of high-rate continuous performance and biofilm layer formation in a H-producing dynamic membrane bioreactor, composed of a continuously stirred tank reactor along with an external module containing polyester mesh with a pore size of 100 µm. A maximum H production rate of 48.9 L/L-day and hydrogen yield of 2.

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A single nucleotide polymorphism of rs1360780 in the FKBP5 gene is associated with a predisposition to developing major depressive disorder (MDD). We investigated the interactive effects of FKBP5 rs1360780 allelic variants, DNA methylation, and the diagnosis of MDD on structural changes of the entire brain. One hundred and fourteen patients with MDD and eighty-eight healthy controls underwent T1-weighted structural magnetic resonance imaging and FKBP5 rs1360780 genotyping, including DNA methylation of intron 7.

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Background: Morphologic changes of the brainstem in major depressive disorder (MDD) have rarely been reported in neuroimaging studies, even though, monoaminergic neurotransmitters are synthesized in several brainstem regions. We aimed to investigate volume changes in each region of the brainstem and their association with antidepressant use or the remission status of MDD.

Methods: A total of 126 patients with MDD and 101 healthy controls underwent T1-weighted structural magnetic resonance imaging.

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Background: Hippocampal volume loss is known as the best-replicated finding of structural brain imaging studies on major depressive disorder (MDD). Several evidences suggest localized mechanisms of hippocampal neuroplasticity lead the brain imaging studies on the hippocampus and MDD to perform analyses in the subfield level. The aim of this study was to investigate the differences in total and subfield hippocampal volumes, between medication-naïve female MDD patients and healthy controls, through automated segmentation and volumetric methods.

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