Publications by authors named "Heeyoung Park"

Rational reforming of metal oxide has a potential importance to modulate their inherent properties toward appealing characteristics for various applications. Here, we present a detailed fundamental study of the proton migration phenomena between mediums and propose the methodology for controllable metal oxide hydrogenation through galvanic reactions with metallic cation under ambient atmosphere. As a proof of concept for hydrogenation, we study the role of proton adoption on the structural properties of molybdenum trioxide, as a representative, and its impact on redox characteristics in Li-ion battery (LiB) systems using electrochemical experiments and first-principles calculation.

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β-PIX, a Rac1/Cdc42-specific guanine nucleotide exchange factor, is known to regulate actin cytoskeleton remodeling during cell migration. In this study, we investigated the effects of β-PIX-d, an isoform of β-PIX, on neocortical development and neuritogenesis. Overexpression of β-PIX-d in the embryonic neocortex induced increased cell clusters and enhanced neurite outgrowth in cortical neurons.

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Mucic acid holds promise as a platform chemical for bio-based nylon synthesis; however, its biological production encounters challenges including low yield and productivity. In this study, an efficient and high-yield method for mucic acid production was developed by employing genetically engineered Saccharomyces cerevisiae expressing the NAD-dependent uronate dehydrogenase (udh) gene. To overcome the NAD dependency for the conversion of pectin to mucic acid, xylose was utilized as a co-substrate.

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Expression changes for tryptophan hydroxylase 1 (TPH1), the rate-limiting enzyme in serotonin synthesis, by environmental glutamine (GLN) were examined in mouse mastocytoma-derived P815-HTR cells. GLN-treated cells exhibited a robust increase in TPH1 mRNA after a 6 h exposure to GLN. 6-Diazo-5-oxo-L-norleucine (DON), a glutamine-utilizing glutaminase inhibitor, significantly inhibited the GLN-induction of TPH1 mRNA.

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Article Synopsis
  • - Metastable phases, which are temporarily stable structures formed under certain conditions, are commonly found in nature and can have better properties than their stable counterparts, making them valuable in materials science.
  • - Crystals often start as metastable phases influenced by factors like temperature and pressure, and they typically transition to more stable forms as they grow over time.
  • - A new approach for discovering metastable materials involves rational design rather than relying on intuition, as demonstrated by the creation of a unique metastable hexagonal close-packed palladium hydride (PdH) through precise control of precursor concentrations.
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The purpose of this study is to establish a practical simulation model based on mass balance, mass transport equations and equilibrium equation between gas and liquid phases across a porous membrane in membrane contactor process in order to predict the separation behavior by the gassing process of gas mixture in membrane contactor. The established simulation model was verified by comparison between the simulated values and real process values in the separation of CH/CO mixture, showing an excellent agreement between them. The parameter R-value in the model, which is a kind of the permeability of permeant across porous membrane, has been determined by fitting a numerical solution of the model equation to the experimental data to obtain a practical value of the parameter.

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Introduction: Decellularized larynges could be used as scaffolds to regenerate the larynx. The purpose of this study was to establish a perfusion decellularization protocol to produce a 3-dimensional whole laryngeal extracellular matrix (ECM) scaffold in a rabbit model.

Methods: The larynges of 20 rabbits assigned to the study group were harvested and decellularized using a perfusion decellularization protocol, while the larynges of 10 rabbits in the control group were harvested and untreated.

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The purpose of this study was to investigate the effect of the aliphatic moiety in the sulfonated poly(arylene ether sulfone) (SPAES) backbone. A new monomer (4,4'-dihydroxy-1,6-diphenoxyhexane) was synthesized and polymerized with other monomers to obtain partially alkylated SPAESs. According to differential scanning calorimetry analysis, the glass transition temperature (T) of these polymers ranged from 85 to 90 °C, which is 100 °C lower than that of the fully aromatic SPAES.

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Being a microbial host for lignocellulosic biofuel production, needs to be engineered to express a heterologous xylose pathway; however, it has been challenging to optimize the engineered strain for efficient and rapid fermentation of xylose. Deletion of (Δ) has been reported to be a crucial genetic perturbation in improving xylose fermentation. A confirmed mechanism of the Δ effect on xylose fermentation is that the Δ transcriptionally activates the genes in the non-oxidative pentose phosphate pathway (PPP).

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Polystyrene-based polymers with variable molecular weights are prepared by radical polymerization of styrene. Polystyrene is grafted with bromo-alkyl chains of different lengths through Friedel-Crafts acylation and quaternized to afford a series of hydroxide-ion-conducting ionomers for the catalyst binder for the membrane electrode assembly in anion-exchange membrane fuel cells (AEMFCs). Structural analyses reveal that the molecular weight of the polystyrene backbone ranges from 10,000 to 63,000 g mol, while the ion exchange capacity of quaternary-ammonium-group-bearing ionomers ranges from 1.

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In the quest to reduce global food loss and waste, fruit processing wastes, particularly citrus peel waste (CPW), have emerged as a promising and sustainable option for biorefinery without competing with human foods and animal feeds. CPW is largely produced and, as recent studies suggest, has the industrial potential of biological valorization into fuels and chemicals. In this review, the promising aspects of CPW as an alternative biomass were highlighted, focusing on its low lignin content.

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Article Synopsis
  • * New mesoporous N-doped carbon/manganese hybrid catalysts (Mn-O/N@NCs) have been developed, showing a high efficiency for the 2e ORR path due to increased Mn-N sites, which promote effective electron transfer.
  • * Testing in a real fuel cell device revealed that the Mn-O/N@NC catalyst maintains stable current output and demonstrates over 80% efficiency in H2O2 production, due to its unique structure supporting rapid mass transport
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expressing heterologous pathways for xylose, arabinose, and galacturonic acid metabolism has been constructed by a Cas9-based genome editing technology [1]. The fermentation performance of the final strain (YE9) was tested under various substrate conditions, and the fermentation parameters were calculated. The dataset can be used for designing bioprocesses for pectin-rich biomass.

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With growing interest in alternative fuels to minimize carbon and particle emissions, research continues on the production of lignocellulosic ethanol and on the development of suitable yeast strains. However, great diversities and continued technical advances in pretreatment methods for lignocellulosic biomass complicate the evaluation of developed yeast strains, and strain development often lags industrial applicability. In this review, recent studies demonstrating developed yeast strains with lignocellulosic biomass hydrolysates are compared.

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Article Synopsis
  • Human palatine tonsils can be a source of multipotent mesenchymal stem cells (TMSCs), which proliferate faster than those from bone marrow (BMSCs) or adipose tissue (ADSCs).
  • The study found that tensin-3 (TNS3) is expressed at higher levels in TMSCs compared to BMSCs and ADSCs, and silencing TNS3 leads to reduced cell growth and alters key signaling pathways.
  • TNS3 appears to influence TMSC proliferation and differentiation by regulating the expression of active integrin beta-1 (ITGβ1), with its inhibition affecting adipogenic and other cell lineage differentiations.
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Pectin-rich biomass has garnered attention as an alternative biomass source. However, some monomers derived from pectin-rich biomass, namely d-galacturonic acid, l-arabinose, and d-xylose, are not fermentable by industrial microorganisms such as Saccharomyces cerevisiae. The purpose of this study is to develop a S.

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Background: This study aimed to investigate the relationships between serum vascular endothelial growth factor (VEGF)-A or VEGF-C levels and lymph node metastasis (LNM) status in patients with papillary thyroid carcinoma (PTC).

Methods: The study enrolled 150 patients with pathologically proven PTC who underwent surgery: PTC without LNM, PTC with central neck metastasis, and PTC with lateral neck metastasis.

Results: Preoperative serum VEGF-A levels were 300.

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Article Synopsis
  • Lysophosphatidic acid (LPA) is a signaling molecule that interacts with specific receptors to influence cellular functions. Recent research identifies an alternative transcription start site for the LPA receptor gene in mice, highlighting unexplored regulatory features of this gene.* -
  • Using a method called 5'RACE analysis, researchers characterized a promoter region crucial for LPA receptor expression, specifically between -248 to +225, which lacks a common TATA box and includes regions that negatively regulate gene expression.* -
  • The study indicates that E-box sequences within the regulatory region impact transcription levels, with one sequence binding to the HeLa E-box binding protein (HEB), suggesting that HEB is vital for proper expression regulation
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Tissue engineering cell-based therapy using induced pluripotent stem cells and adipose-derived stem cells (ASCs) may be promising tools for therapeutic applications in tissue engineering because of their abundance, relatively easy harvesting, and high proliferation potential. The purpose of this study was to investigate whether ASCs can promote the auricular cartilage regeneration in the rabbit. In order to assess their differentiation ability, ASCs were injected into the midportion of a surgically created auricular cartilage defect in the rabbit.

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The goal of this study was to investigate associations between admissions criteria and performance in Ph.D. programs at Boston University School of Medicine.

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Thyroid function decreases and cold exposure response becomes impaired with increasing age. We investigated the age-related changes in thyroid structure and function and cold-induced changes in the thyroid activity of aging rats. Thirty-two male Sprague-Dawley rats were randomly divided into four groups (8 rats per group): young (7 months) and old (22 months) groups exposed to room temperature and cold stress.

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The effect of alloying with transition metals (Ni, Co, Fe) on the adsorption strength of phosphoric acid on Pt alloy surfaces was investigated using electrochemical analysis and first-principles calculations. Cyclic voltammograms of carbon-supported PtM/C (M = Ni, Co, and Fe) electrocatalysts in 0.1 M HClO with and without 0.

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Background: Although indoleamine 2,3-dioxygenase (IDO)-mediated immune suppression of mesenchymal stem cells (MSCs) has been revealed in septic and tumor microenvironments, the role of IDO in suppressing allergic airway inflammation by MSCs is not well documented. We evaluated the effects of adipose-derived stem cells (ASCs) on allergic inflammation in IDO-knockout (KO) asthmatic mice or asthmatic mice treated with ASCs derived from IDO-KO mice.

Methods And Findings: ASCs were injected intravenously in wild-type (WT) and IDO-KO asthmatic mice.

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Human mesenchymal stem cells (MSCs) are a promising tool for therapeutic applications in cell-based therapy and regenerative medicine, and MSCs from the human palatine tonsils have recently been used as a new tissue source. However, the understanding of the proliferation and differentiation capacity of tonsil-derived MSCs (T-MSCs) is limited. In this study, we compared the proliferative potential of T-MSCs with those of bone marrow MSCs (BM-MSCs) and adipose tissue-derived MSCs (A-MSCs).

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Objectives: The clinical application of allogenic and/or xenogenic cartilage for vocal fold augmentation requires to remove the antigenic cellular component. The objective of this study was to assess the effect of cartilage decellularization and determine the change in immunogenicity after detergent treatment in human nasal septal cartilage flakes made by the freezing and grinding method.

Methods: Human nasal septal cartilages were obtained from surgical cases.

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