Publications by authors named "Jiyong Park"

68 Publications

Medico-legal implications for the colon perforation during colonoscopy.

J Forensic Leg Med 2021 May 12;80:102185. Epub 2021 May 12.

Department of Nursing, Gwangju University, Gwangju, Republic of Korea. Electronic address:

Colon perforation is the most serious complication of colonoscopy, and tends to be considered as malpractice. The aim of this study was to identify the characteristics and causes of medical accidents by analyzing lawsuit cases on colon perforation during colonoscopy. We collected judgment results that were ruled from 2005 to 2015 using the keyword 'colonoscopy' in the 'Korea's Written Judgment Public Reading System' of the Supreme Court, and extracted the cases of colon perforation. Characteristics of medical accidents and the decisions of courts were analyzed from written judgments. Twenty-two lawsuits were analyzed. Most cases were ruled in favor of the plaintiff (n = 20). The allegations against defendants, as filed by the plaintiffs, were performance error (n = 22), improper monitoring after colonoscopy (n = 7), and a lack of informed consent (n = 8). The median compensation was 9335.47 US dollars; this is about 130 times the cost of a single colonoscopy in Korea. The greater the intestinal damage, the greater the amount of compensation (p = 0.016). The time interval from procedure to diagnosis of perforation was most frequently 24 h later (n = 9). It is important to educate patients completely about the symptoms of colon perforation and to guide them to contact medical institutions immediately when symptoms occur. In addition, doctors should explain sufficiently the possibility of perforation before colonoscopy to the patient, and not the caregiver, and get informed consent.
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http://dx.doi.org/10.1016/j.jflm.2021.102185DOI Listing
May 2021

Enhanced Osteogenic Differentiation of Periodontal Ligament Stem Cells Using a Graphene Oxide-Coated Poly(ε-caprolactone) Scaffold.

Polymers (Basel) 2021 Mar 5;13(5). Epub 2021 Mar 5.

Department of Biosystems Engineering, College of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea.

Periodontal diseases occur through bacterial infection in the oral cavity, which can cause alveolar bone loss. Several efforts have been made to reconstruct alveolar bone, such as grafting bone substitutes and 3D-printed scaffolds. Poly(ε-caprolactone) (PCL) is biocompatible and biodegradable, thus demonstrating its potential as a biomaterial substitute; however, it is difficult for cells to adhere to PCL because of its strong hydrophobicity. Therefore, its use as a biomaterial has limitations. In this study, we used graphene oxide (GO) as a coating material to promote the osteogenic differentiation ability of PCL scaffolds. First, 3D-printed PCL scaffolds were fabricated, and the oxygen plasma treatment and coating conditions were established according to the concentration of GO. The physical and chemical properties of the prepared scaffolds were evaluated through water contact angle analysis, Raman spectroscopy, and image analysis. In addition, the adhesion and proliferation of periodontal ligament stem cells (PDLSCs) on the GO scaffolds were assessed via the water-soluble tetrazolium salt-1 (WST-1) assay, and the osteogenic differentiation ability was evaluated through alizarin red S staining. The results confirmed that the cell proliferation and osteogenic differentiation of the PDLSCs were enhanced in the scaffolds coated with oxygen plasma and GO. In conclusion, the plasma-treated GO-coating method that we developed can be used to promote the cell proliferation and osteogenic differentiation of the scaffolds.
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http://dx.doi.org/10.3390/polym13050797DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7961340PMC
March 2021

Formation of furan in baby food products: Identification and technical challenges.

Compr Rev Food Sci Food Saf 2021 May 14;20(3):2699-2715. Epub 2021 Mar 14.

Department of Biotechnology, Yonsei University, Seoul, South Korea.

Furan is generally produced during thermal processing of various foods including baked, fried, and roasted food items such as cereal products, coffee, canned, and jarred prepared foods as well as in baby foods. Furan is a toxic and carcinogenic compound to humans and may be a vital hazard to infants and babies. Furan could be formed in foods through thermal degradation of carbohydrates, dissociation of amino acids, and oxidation of polyunsaturated fatty acids. The detection of furan in food products is difficult due to its high volatility and low molecular weight. Headspace solid-phase microextraction coupled with gas chromatography/mass spectrometer (GC/MS) is generally used for analysis of furan in food samples. The risk assessment of furan can be characterized using margin of exposure approach (MOE). Conventional strategies including cooking in open vessels, reheating of commercially processed foods with stirring, and physical removal using vacuum treatment have remained unsuccessful for the removal of furan due to the complex production mechanisms and possible precursors of furan. The innovative food-processing technologies such as high-pressure processing (HPP), high-pressure thermal sterilization (HPTS), and Ohmic heating have been adapted for the reduction of furan levels in baby foods. But in recent years, only HPP has gained interest due to successful reduction of furan because of its nonthermal mechanism. HPP-treated baby food products are commercially available from different food companies. This review summarizes the mechanism involved in the formation of furan in foods, its toxicity, and identification in infant foods and presents a solution for limiting its formation, occurrence, and retention using novel strategies.
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http://dx.doi.org/10.1111/1541-4337.12732DOI Listing
May 2021

Extract of high hydrostatic pressure-treated danshen (Salvia miltiorrhiza) ameliorates atherosclerosis via autophagy induction.

BMB Rep 2020 Dec;53(12):652-657

Chemical Genomics Global Research Lab, Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, Korea.

Danshen (Salvia miltiorrhiza) is a traditional medicinal plant widely used in Asian countries for its pharmacological activities (e.g., amelioration of cardiovascular diseases). In this study, we investigated the anti-atherosclerotic activity of raw danshen root extract prepared using high hydrostatic pressure (HHP) at 550 MPa for 5 min and hot water extraction. This method was useful for elimination of bacteria from cultured danshen plants and for better extraction yield of active principles. The HHPtreated danshen extract (HDE) inhibited proliferation of human umbilical vein endothelial cells (HUVECs) and induced autophagy that was assessed by LC3 conversion and p62 degradation. HDE suppressed foam cell formation in oxLDL-induced RAW264.7 macrophages; lysosomal activity simultaneously increased, measured by acridine orange staining. HDE also reduced atherosclerotic plaque development in vivo in apolipoprotein E knock-out (ApoE-/-) mice fed a high cholesterol diet. Taken together, these results indicated that HDE exhibited anti-atherosclerotic activity via autophagy induction. [BMB Reports 2020; 53(12): 652-657].
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7781913PMC
December 2020

Antioxidant and anti-inflammatory activities of phenolic compounds extracted from lemon myrtle () leaves at various extraction conditions.

Food Sci Biotechnol 2020 Oct 29;29(10):1425-1432. Epub 2020 Aug 29.

Department of Biotechnology, Yonsei University, Seoul, 03722 Republic of Korea.

Lemon myrtle leaves were extracted with ethanol at different temperatures (25, 50, and 80 °C) and times (2, 4, 6, and 10 h) to examine the effect of extraction conditions on total polyphenol contents (TPC), total flavonoid contents (TFC), their antioxidant, anti-inflammatory activities, and amount of phenolic compounds. Under optimal extraction conditions (80 °C and 6 h), the values were 23.37%, 102.72 mg gallic acid equivalents (GAE/g dry basis), 23.37 mg rutin equivalents (RE/g dry basis), 83.31%, 60.13%, and 1.10% for yield, TPC, TFC, DPPH, ABTS radical scavenging activity, and reducing power, respectively. In addition, total amount of the phenolic compounds of extract was determined as 43.9 μg/g. The anti-inflammatory effect was determined in lipopolysaccharide-stimulated RAW 264.7 cells and inhibited the production of inflammatory mediators such as nitric oxide (NO). These results indicate that extracts of lemon myrtle leaves have potential as a valuable natural product with antioxidant and anti-inflammatory.
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http://dx.doi.org/10.1007/s10068-020-00795-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7492333PMC
October 2020

Characteristics of wheat starch-pectin hydrolysate complexes by dry heat treatment.

Food Sci Biotechnol 2020 Oct 1;29(10):1389-1399. Epub 2020 Aug 1.

Department of Biomaterial Science and Engineering, Yonsei University, Seoul, 03722 Korea.

The objective of this study was to characterize dry heat-induced wheat starch-pectin hydrolysate (WST/PH) complexes to develop the retrogradation-retarded starch. Native (N-) and protease-treated (P-) WST were used as starch sources. Pectin hydrolysates were mixed independently with N-WST and P-WST to a mixing ratio of 49:1 (based on total solid contents), followed by drying below 10% moisture and dry heat treatment at 130 °C for 4 h. The molar degrees of substitution (MS) was higher for WST/PH complexes than its mixtures, and apparent amylose contents decreased with their MS. Relative to WST/PH mixtures, solubilities were higher for WST/PH complexes, while swelling powers didn't differ. WST/PH complexes showed the lower degree of retrogradation, setback viscosities, slowly gelling tendency, and syneresis. These phenomena were more pronounced in WST/PH mixtures and complexes prepared with P-WST. Overall results suggest that dry heat-induced WST/PH complexes could be a potential retrogradation-retarded starch to replace chemically-modified starches.
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http://dx.doi.org/10.1007/s10068-020-00796-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7492329PMC
October 2020

Optimization of phytic acid-crosslinked chitosan microspheres for oral insulin delivery using response surface methodology.

Int J Pharm 2020 Oct 3;588:119736. Epub 2020 Aug 3.

Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, South Korea. Electronic address:

Although oral administration is favorable mode of insulin delivery, it is the most challenging route, owing to poor oral bioavailability. In this study, a chitosan (CS)-based insulin delivery system was developed by ionic crosslinking with phytic acid (PA). CS-PA microspheres were optimized with different crosslinking conditions of CS and PA using response surface methodology to retain insulin during preparation and gastric digestion. Furthermore, the in vitro release profile, morphological structure, cytotoxicity, and intestinal permeability of the optimized microspheres, and its hypoglycemic effect in diabetic rats were evaluated. Under optimal conditions, the entrapment efficiency was 97.1%, and 67.0% of insulin was retained in the microspheres after 2 h of gastric digestion followed by a sustained-release in intestinal fluid. Insulin was primarily distributed in the microsphere core with a monodisperse diameter of 663.3 μm. The microspheres increased the permeability of insulin across Caco-2/HT-29 monolayers by 1.6 times with negligible cytotoxicity. The microspheres had a relative pharmacological bioavailability of 10.6% and significantly reduced blood glucose levels with a long-lasting hypoglycemic effect after oral administration in diabetic rats. This study demonstrated that an optimized formulation of a simple ionic crosslinking system using CS and PA could facilitate efficient oral delivery of insulin.
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http://dx.doi.org/10.1016/j.ijpharm.2020.119736DOI Listing
October 2020

Supramolecular Fullerene Tetramers Concocted with Porphyrin Boxes Enable Efficient Charge Separation and Delocalization.

J Am Chem Soc 2020 07 27;142(29):12596-12601. Epub 2020 Jun 27.

Center for Self-assembly and Complexity, Institute for Basic Science, Pohang 37673, Republic of Korea.

Herein, we report a novel porphyrin/fullerene supramolecular cocrystal using a shape-persistent zinc-metalated porphyrin box (Zn-PB) and C/C. An unprecedented arrangement of a tightly packed square-planar core of four C or C surrounded by six cube-shaped Zn-PBs was observed. This unique packing promotes strong charge transfer (CT) interactions between the two components in the ground state and formation of charge-separated states with very long lifetimes in the excited state and enables unusually high photoconductivity. Quantum chemical calculations show that these features are enabled by delocalized orbitals that promote the CT, on one hand, and that are spatially separated from each other, on the other hand. This work may open a new avenue to design novel electron donor/acceptor architectures for artificial photosynthesis.
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http://dx.doi.org/10.1021/jacs.0c05339DOI Listing
July 2020

High-Efficiency Diphenylpyrimidine Derivatives Blue Thermally Activated Delayed Fluorescence Organic Light-Emitting Diodes.

Front Chem 2020 14;8:356. Epub 2020 May 14.

Department of Chemistry and Research Institute for Green Energy Convergence Technology, Gyeongsang National University, Jinju-si, South Korea.

Organic light-emitting diodes with thermally activated delayed fluorescence emitter have been developed with highly twisted donor-acceptor configurations and color-pure blue emitters. Synthesized 4-(4-(4,6-diphenylpyrimidin-2-yl)phenyl)-10H-spiro[acridine-9,9'-fluorene] (4,6-PhPMAF) doped device with spiroacridine as a donor unit and diphenylpyrimidine as acceptor exhibits the device characteristics such as the luminescence, external quantum efficiencies, current efficiencies, and power efficiencies corresponding to 213 cd/m, 2.95%, 3.27 cd/A, and 2.94 lm/W with Commission International de l'Eclairage (CIE) coordinates of (0.15, 0.11) in 4,6-PhPMAF-doped DPEPO emitter. The reported 10-(4-(2,6-diphenylpyrimidin-4-yl)phenyl)-10H-spiro[acridine-9,9'-fluorene] (2,6-PhPMAF) doped device exhibit high device performance with 1,445 cd/m, 12.38%, 19.6 cd/A, and 15.4 lm/W, which might be originated from increased internal quantum efficiency by up-converted triplet excitons to the singlet state with relatively smaller Δ of 0.17 eV and higher reverse intersystem crossing rate ( ) of 1.0 ×10/s in 2,6-PhPMAF than 0.27 eV and 3.9 ×10/s in 4,6-PhPMAF. Despite low performance of 4,6-PhPMAF doped device, synthesized 4,6-PhPMAF has better color purity as a deep-blue emission with axis (0.11) than reported 2,6-PhPMAF with axis (0.19) in CIE coordinate. The synthesized 4,6-PhPMAF has higher thermal stability of any transition up to 300°C and decomposition temperature with only 5% weight loss in 400°C than reported 2,6-PhPMAF. The maximum photoluminescence emission of 4,6-PhPMAF in various solvents appeared at 438 nm, which has blue shift about 20 nm than that of 2,6-PhPMAF, which contributes deep-blue emission in synthesized 4,6-PhPMAF.
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http://dx.doi.org/10.3389/fchem.2020.00356DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7240071PMC
May 2020

Improved effect of palatinose syrup bioconverted from sucrose on hyperglycemia and regulation of hepatic lipogenesis in male C57BL/6J mice.

J Food Biochem 2020 05 15;44(5):e13201. Epub 2020 Mar 15.

Department of Food Science and Biotechnology, Kyonggi University, Suwon, Republic of Korea.

In this study, we prepared palatinose-sucrose (PS) mixtures from sucrose by enzymatic bioconversion to improve the low sweetness of palatinose and to develop sweeteners that can lower blood sugar levels. We hypothesized that PS mixtures containing 30% or 50% palatinose might demonstrate improvement of hyperglycemia. The physiological changes in C57BL/6J mice fed with these concentrations of PS mixture were recorded. After feeding the mice the different diets for 5 weeks, the diet with a higher palatinose content was observed to have resulted in lower serum glucose levels. The expression levels of various genes and proteins related to hepatic lipogenesis and cholesterol homeostasis were measured. The diet containing the 50% PS mixture induced lower expression of HMGCR, CYP7A1, and PPARγ as compared to the diet containing the 30% PS mixture. In conclusion, the ingestion of palatinose resulted in lower lipid levels compared to that of sucrose; therefore, palatinose would be a good alternative to sucrose as a healthy sweetener. PRACTICAL APPLICATIONS: Palatinose (isomaltulose), along with tagatose, allulose, and allose, is a well-known sugar substitute. Many studies have reported that palatinose has various beneficial effects on postprandial glucose metabolism, such as glycemic index, fat accumulation, hyperglycemia, and hyperinsulinemia. Although there are many advantages, including desirable biological functions, palatinose has limitations as a complete alternative for sucrose because of higher production costs, lower solubility, and lower sweetness. Therefore, we aimed to investigate the possibility of developing a sucrose substitute by preparing PS mixtures bioconverted using α-glucosyltransferase from sucrose and to promote the industrial application of palatinose. Our results suggest that 50% palatinose syrup may be a new candidate as a sugar substitute for industrial application.
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http://dx.doi.org/10.1111/jfbc.13201DOI Listing
May 2020

Impact of Visceral Obesity on the Risk of Incident Metabolic Syndrome in Metabolically Healthy Normal Weight and Overweight Groups: A Longitudinal Cohort Study in Korea.

Korean J Fam Med 2020 Jul 29;41(4):229-236. Epub 2020 Apr 29.

Department of Family Medicine, Healthcare System Gangnam Center, Seoul National University Hospital, Seoul, Korea.

Background: Although both obesity, measured by body mass index, and visceral obesity are known to be major risk factors of metabolic syndrome and its components, there have been debates on the relative contribution of general obesity and visceral obesity to the development of metabolic syndrome.

Methods: We performed a large longitudinal cohort study of 3,093 subjects (age range, 18-65 years) who were metabolically healthy and had a normal weight who received health screenings over a 3-year follow-up period. Cox proportional hazards models were used to estimate the adjusted hazard ratios (HRs) and 95% confidence intervals (CI) for incident metabolic syndrome and its components per sex-specific 1-standard deviation (SD) increase in visceral adipose tissue (VAT) and body mass index.

Results: Both obesity and visceral obesity increased the risk of incident metabolic syndrome, but when HR was compared per sex-specific 1-SD, visceral obesity appeared to confer more risk than simple obesity. The HR for 1-SD of body mass index was 1.19 (95% CI, 1.07-1.32; P=0.001) in men and 1.29 (95% CI, 1.10-1.52; P=0.002) in women, while the HR for 1-SD of VAT was 1.29 (95% CI, 1.15-1.44; P<0.001) in men and 1.50 (95% CI, 1.28-1.75; P<0.001) in women.

Conclusion: Visceral obesity and obesity were longitudinally associated with an increased risk of incident metabolic syndrome among metabolically healthy adults, and visceral fat accumulation appears to be better predictor of metabolic syndrome.
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http://dx.doi.org/10.4082/kjfm.18.0122DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7385301PMC
July 2020

Minimalistic Principles for Designing Small Molecules with Multiple Reactivities against Pathological Factors in Dementia.

J Am Chem Soc 2020 05 23;142(18):8183-8193. Epub 2020 Apr 23.

Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea.

Multiple pathogenic elements, including reactive oxygen species, amyloidogenic proteins, and metal ions, are associated with the development of neurodegenerative disorders. We report minimalistic redox-based principles for preparing compact aromatic compounds by derivatizing the phenylene moiety with various functional groups. These molecular agents display enhanced reactivities against multiple targets such as free radicals, metal-free amyloid-β (Aβ), and metal-bound Aβ that are implicated in the most common form of dementia, Alzheimer's disease (AD). Mechanistic studies reveal that the redox properties of these reagents are essential for their function. Specifically, they engage in oxidative reactions with metal-free and metal-bound Aβ, leading to chemical modifications of the Aβ peptides to form covalent adducts that alter the aggregation of Aβ. Moreover, the administration of the most promising candidate significantly attenuates the amyloid pathology in the brains of AD transgenic mice and improves their cognitive defects. Our studies demonstrate an efficient and effective redox-based strategy for incorporating multiple functions into simple molecular reagents.
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http://dx.doi.org/10.1021/jacs.9b13100DOI Listing
May 2020

Development of ginseng powder using high hydrostatic pressure treatment combined with UV-TiO photocatalysis.

J Ginseng Res 2020 Jan 23;44(1):154-160. Epub 2018 Nov 23.

Department of Biotechnology, Yonsei University, Seoul, Republic of Korea.

Background: Korean ginseng ( Meyer) powder is in rising demand because powder forms of foods are convenient to handle and are highly preservable. However, ginseng powder (GP) manufactured using the conventional process of air drying and dry milling suffers nutrient destruction and a lack of microbiological safety. The objective of this study was to prepare GP using a novel process comprised of UV-TiO photocatalysis (UVTP) as a prewashing step, wet grinding, high hydrostatic pressure (HHP), and freeze-drying treatments.

Methods: The effects of UVTP and HHP treatments on the microbial population, ginsenoside concentration, and physiological characteristics of GP were evaluated.

Results: When UVTP for 10 min and HHP at 600 MPa for 5 min were combined, initial 4.95 log CFU/g-fw counts of total aerobes in fresh ginseng were reduced to lower than the detection limit. The levels of 7 major ginsenosides in UVTP-HHP-treated GP were significantly higher than in untreated control samples. Stronger inhibitory effects against inflammatory mediator production and antioxidant activity were observed in UVTP-HHP-treated GP than in untreated samples. There were also no significant differences in CIELAB color values of UVTP-HHP-treated GP compared with untreated control samples.

Conclusion: Combined processing of UVTP and HHP increased ginsenoside levels and enhanced the microbiological safety and physiological activity of GP.
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http://dx.doi.org/10.1016/j.jgr.2018.11.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7033331PMC
January 2020

The Mechanism of Rhodium-Catalyzed Allylic C-H Amination.

J Am Chem Soc 2020 03 13;142(12):5842-5851. Epub 2020 Mar 13.

Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States.

Herein, the mechanism of catalytic allylic C-H amination reactions promoted by Cp*Rh complexes is reported. Reaction kinetics experiments, stoichiometric studies, and DFT calculations demonstrate that the allylic C-H activation to generate a Cp*Rh(π-allyl) complex is viable under mild reaction conditions. The role of external oxidants in the catalytic cycle is elucidated. Quantum mechanical calculations, stoichiometric reactions, and cyclic voltammetry experiments concomitantly support an oxidatively induced reductive elimination process of the allyl fragment with an acetate ligand proceeding through a Rh(IV) intermediate. Stoichiometric oxidation and bulk electrolysis of the proposed π-allyl intermediate are also reported to support these analyses. Lastly, evidence supporting the amination of an allylic acetate intermediate is presented. We show that Cp*Rh(III) behaves as a Lewis acid catalyst to complete the allylic amination reaction.
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http://dx.doi.org/10.1021/jacs.0c01069DOI Listing
March 2020

Anti-Cancer Effects of Berry Polysaccharides Activation of Immune-Related Cells.

Front Pharmacol 2019 26;10:1411. Epub 2019 Nov 26.

Department of Food Science and Biotechnology, Kyonggi University, Suwon, South Korea.

has long been used as natural medicine and health food all over the world. Cancer is a major cause of death worldwide and its prognosis likely depends on the immune system during tumor treatment. In this study, ginseng berry polysaccharides were evaluated for their immunostimulant and anti-cancer effects. Ginseng berry polysaccharide portion (GBPP) was used to investigate its effects on anti-complementary activity, peritoneal macrophage activation, and natural killer (NK) cell cytotoxicity. Moreover, both intravenous () and oral administration of GBPP prior to B16-BL6 melanoma implantation in mice was evaluated. GBPP significantly increased the anti-complementary activity and cytokine production including interleukin (IL)-6, IL-12, and tumor necrosis factor (TNF)-α, dose-dependently. Splenocytes obtained after administration of GBPP showed cytolytic activity in Yac-1 cells in proportion to the E/T ratio. In addition, GBPP enhanced the production of interferon (IFN)-γ and granzyme B of NK cells. For the experimental lung cancer, compared with control mice, GBPP delivered by suppressed cancer by 48% at 100 μg/mouse, while a 37% reduction was achieved by oral administration. Deficient of NK cells in animal model demonstrated that the anti-cancer effect of GBPP was through NK cell activation. Results of this study suggest that ginseng berry polysaccharides, owing to their modulation of the immune response, can be a potential curative applicant for the prevention and treatment of tumors.
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http://dx.doi.org/10.3389/fphar.2019.01411DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6988799PMC
November 2019

Entropic nonclassicality and quantum non-Gaussianity tests via beam splitting.

Sci Rep 2019 Nov 28;9(1):17835. Epub 2019 Nov 28.

School of Computational Sciences, Korea Institute for Advanced Study, Seoul, 02455, Korea.

We propose entropic nonclassicality criteria for quantum states of light that can be readily tested using homodyne detection with beam splitting operation. Our method draws on the fact that the entropy of quadrature distributions for a classical state is non-increasing under an arbitrary loss channel. We show that our test is strictly stronger than the variance-based squeezing condition and that it can also be extended to detect quantum non-Gaussianity in conjunction with phase randomization. Furthermore, we address how our criteria can be used to identify single-mode resource states to generate two-mode states demonstrating EPR paradox, i.e., quantum steering, via beam-splitter setting.
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http://dx.doi.org/10.1038/s41598-019-54110-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6882878PMC
November 2019

Rigorous single pulse imaging for ultrafast interferometric observation.

Opt Express 2019 Jul;27(14):19758-19767

We discuss how to realize rigorous single pulse imaging using a fiber mode-locked laser for the purpose of ultrafast interferometric observation of fast varying dynamic objects. Sub-picosecond pulses are readily picked up in synchronization with the camera operation, allocating one pulse per frame, but rigorous ultrashort single pulse imaging is disturbed by the accumulation of amplified spontaneous emission (ASE) over the exposure time of the camera. Here, we propose four distinct methods to eliminate the ASE-accumulated disruption in the ultrashort optical gating by pulse interferometry and then evaluate their merits and limitations individually by experiments. The proposed four methods are referred to respectively as the time averaged phase modulation, unbalanced pulse overlapping, tandem pulse picking, and second harmonic generation.
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http://dx.doi.org/10.1364/OE.27.019758DOI Listing
July 2019

Dynamic Kinetic Resolution of Alkenyl Cyanohydrins Derived from α,β-Unsaturated Aldehydes: Stereoselective Synthesis of -Tetrasubstituted Olefins.

J Am Chem Soc 2019 07 22;141(30):11770-11774. Epub 2019 Jul 22.

Department of Chemistry , Queen's University , 90 Bader Lane , Kingston , Ontario K7L 3N6 , Canada.

A novel dynamic kinetic resolution (DKR) of tetrasubstituted alkenyl cyanohydrins prepared from the corresponding α,β-unsaturated aldehydes is described. The deprotonation of a geometrical mixture of tetrasubstituted alkenyl cyanohydrins with sodium diisopropylamide (NaDA) affords the allylic anions, which enables the equilibration of the - and -olefins to permit the selective functionalization of the -adduct. Theoretical studies indicate that the nature of the alkali metal cation is a critical component to lowering the barrier for interconversion between the two geometrical isomers, which provides the mechanistic basis for the DKR reaction. In addition, we demonstrate that the DKR reaction can be combined with a transition metal-catalyzed allylic substitution to generate a stereodefined -tetrasubstituted olefin and quaternary center in a single cross-coupling reaction.
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http://dx.doi.org/10.1021/jacs.9b04384DOI Listing
July 2019

Immunostimulating and Antimetastatic Effects of Polysaccharides Purified from Ginseng Berry.

Am J Chin Med 2019 15;47(4):823-839. Epub 2019 May 15.

* Department of Food Science and Biotechnology, Kyonggi University, Suwon, Gyeonggi-do 16227, Republic of Korea.

Ginseng root has been used in traditional oriental medicine for the enhancement of immune system function. The immunostimulatory effects of ginseng berry polysaccharides, however, remain unclear. Effects of polysaccharides from ginseng berry on the activation of natural killer (NK) cells and inhibition of tumors are reported. A crude polysaccharide was isolated from ginseng berry as a ginseng berry polysaccharide portion (GBPP) and was further fractionated using gel filtration chromatography to obtain the three polysaccharide fractions GBPP-I, -II and -III. GBPP-I consisted of mainly galactose (46.9%) and arabinose (27.5%). GBPP-I showed a high dose-dependent anticomplementary activity. Stimulation of murine peritoneal macrophages by GBPP-I showed the greatest enhancement of interleukin (IL)-6 and IL-12 and tumor necrosis factor (TNF)- production. In addition, an assay of natural killer (NK) cell activity showed that oral ( administration of GBPP-I significantly increased NK cell cytotoxicity in YAC-1 tumor cells and production of granzyme B. Prophylactic intravenous ( and administration of GBPP-I significantly and dose-dependently inhibited lung metastatic activity in B16BL6 melanoma cells. Depletion of NK cells after injection of rabbit anti-asialo GM1 partially abolished the inhibitory effect of GBPP-I on lung metastasis, indicating that NK cells play an important role in anticancer effects. GBPP-I exerts a strong immune-enhancing activity and can prevent cancer metastasis through activation of NK cells and other immune-related cells.
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http://dx.doi.org/10.1142/S0192415X19500435DOI Listing
October 2019

Data-driven synthetic MRI FLAIR artifact correction via deep neural network.

J Magn Reson Imaging 2019 11 18;50(5):1413-1423. Epub 2019 Mar 18.

Department of Electrical and Electronic Engineering, Yonsei University, Seoul, Republic of Korea.

Background: FLAIR (fluid attenuated inversion recovery) imaging via synthetic MRI methods leads to artifacts in the brain, which can cause diagnostic limitations. The main sources of the artifacts are attributed to the partial volume effect and flow, which are difficult to correct by analytical modeling. In this study, a deep learning (DL)-based synthetic FLAIR method was developed, which does not require analytical modeling of the signal.

Purpose: To correct artifacts in synthetic FLAIR using a DL method.

Study Type: Retrospective.

Subjects: A total of 80 subjects with clinical indications (60.6 ± 16.7 years, 38 males, 42 females) were divided into three groups: a training set (56 subjects, 62.1 ± 14.8 years, 25 males, 31 females), a validation set (1 subject, 62 years, male), and the testing set (23 subjects, 57.3 ± 20.4 years, 13 males, 10 females).

Field Strength/sequence: 3 T MRI using a multiple-dynamic multiple-echo acquisition (MDME) sequence for synthetic MRI and a conventional FLAIR sequence.

Assessment: Normalized root mean square (NRMSE) and structural similarity (SSIM) were computed for uncorrected synthetic FLAIR and DL-corrected FLAIR. In addition, three neuroradiologists scored the three FLAIR datasets blindly, evaluating image quality and artifacts for sulci/periventricular and intraventricular/cistern space regions.

Statistical Tests: Pairwise Student's t-tests and a Wilcoxon test were performed.

Results: For quantitative assessment, NRMSE improved from 4.2% to 2.9% (P < 0.0001) and SSIM improved from 0.85 to 0.93 (P < 0.0001). Additionally, NRMSE values significantly improved from 1.58% to 1.26% (P < 0.001), 3.1% to 1.5% (P < 0.0001), and 2.7% to 1.4% (P < 0.0001) in white matter, gray matter, and cerebral spinal fluid (CSF) regions, respectively, when using DL-corrected FLAIR. For qualitative assessment, DL correction achieved improved overall quality, fewer artifacts in sulci and periventricular regions, and in intraventricular and cistern space regions.

Data Conclusion: The DL approach provides a promising method to correct artifacts in synthetic FLAIR.

Level Of Evidence: 4 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;50:1413-1423.
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http://dx.doi.org/10.1002/jmri.26712DOI Listing
November 2019

Nanoparticle-Patterned Multicompartmental Chitosan Capsules for Oral Delivery of Oligonucleotides.

ACS Biomater Sci Eng 2018 Dec 30;4(12):4163-4173. Epub 2018 Nov 30.

Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea.

Orally administered antisense therapy has been introduced as an effective approach for treating cancer in the gastrointestinal tract. However, its practical application has been limited by the instability of oligonucleotides and their inefficient delivery. To overcome these problems, we synthesized size-dependent, oligonucleotide nanoparticle-patterned chitosan/phytic acid (ODN/CS/PA) capsules with protective shields via a three-step process of self-assembly, nanoparticle encapsulation, and shell formation. The multicompartmental capsule size and oligonucleotide nanoparticle-loading pattern were controlled by applying different potentials during the electrostatic extrusion process used for nanoparticle encapsulation. Over 95% of encapsulated oligonucleotides were protected from nuclease digestion (DNase I) and, depending on their size, showed 40-75% protection against simulated gastric fluid. Their controlled release from capsules correlated with the cellular delivery of released nanoparticles and the inhibition of protein expression in cancer cells. Specifically, large capsules showed approximately 32-fold greater delivery to cancer cells than nonencapsulated nanoparticles. We also confirmed delivery of oligonucleotide nanoparticles to the small intestine and colon of rats following oral administration. These findings demonstrate that the multicompartmental ODN/CS/PA capsules can facilitate efficient oral delivery of oligonucleotides for cancer treatment.
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http://dx.doi.org/10.1021/acsbiomaterials.8b00806DOI Listing
December 2018

Inactivation of Typhimurium in fresh cherry tomatoes using combined treatment of UV-TiO photocatalysis and high hydrostatic pressure.

Food Sci Biotechnol 2018 Oct 6;27(5):1531-1539. Epub 2018 Apr 6.

2Department of Biotechnology, Yonsei University, Seoul, 03722 South Korea.

The antibacterial efficacy of UV-TiO photocatalysis pre-washing in a water-assisted system (UVT, 4.5 mW/cm, 5-15 min) and high hydrostatic pressure (HHP, 300-500 MPa, 1 min at 25 °C) post-package combined treatment was evaluated against Typhimurium inoculated onto whole cherry tomato surfaces and compared with chlorine disinfection (200 ppm). An air pump was fitted at the bottom of UVT reactor to create turbulent flow for rotation of fruits for uniform disinfection. UVT-HHP combined treatment at 500 MPa achieved bacterial reduction of more than 5 log via a synergistic effect, compared with chlorine disinfection. Lycopene and total phenolic contents and antioxidant activities were not significantly changed in tomatoes after any treatment. UVT-HHP combined treatment did not affect the surface color but caused softness in tomatoes. UVT pre-washing followed by HHP post-package treatment can be the effective intervention strategy alternative to conventional chlorine disinfection for production of ready-to-eat (RTE) fresh cherry tomatoes.
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http://dx.doi.org/10.1007/s10068-018-0368-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6170276PMC
October 2018

Palladium-Catalyzed Divergent Cyclopropanation by Regioselective Solvent-Driven C(sp )-H Bond Activation.

Angew Chem Int Ed Engl 2018 Nov 24;57(47):15460-15464. Epub 2018 Oct 24.

Department of Chemistry and Nanoscience (BK21 PLUS), Ewha Womans University, Seoul, 03760, Republic of Korea.

Reported is a tandem palladium-catalyzed Heck/regioselective C(sp )-H activation reaction for the divergent synthesis of spiro- and fused-cyclopropanated indolines from N-methallylated 2-bromoarylamides. The regioselectivity of the C-H bond activation in the σ-alkylPd intermediate is controlled by the solvent used. DFT calculations suggest that the polarity of solvent molecules could influence the transition-state energy, leading to a bifurcation of the C-H bond activation in the σ-alkylPd intermediate.
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http://dx.doi.org/10.1002/anie.201809133DOI Listing
November 2018

Efficacy of UV-TiO photocatalysis technology for inactivation of Escherichia coli K12 on the surface of blueberries and a model agar matrix and the influence of surface characteristics.

Food Microbiol 2018 Dec 30;76:526-532. Epub 2018 Jul 30.

Department of Biotechnology, Yonsei University, Seoul 03722, South Korea. Electronic address:

Surface disinfection of fresh blueberries is an important food safety challenge due to the delicate texture and short shelf life of these small fruits. A newly designed water-assisted photocatalytic reactor was developed for disinfection of fruits with a delicate texture and complex surface characteristics. Efficacy of UV-TiO photocatalysis was evaluated in comparison with UV alone for inactivation of Escherichia coli K12 (as a surrogate for Escherichia coli O157:H7) inoculated onto the surface of the blueberry skin, calyx, and an experimentally prepared agar matrix that was used as a model matrix. Influence of surface characteristics such as surface hydrophobicity and surface free energy on bacterial adhesion were also investigated. The initial bacterial population on all surfaces was approximately 7.0 log CFU/g. UV-TiO photocatalysis (4.5 mW/cm) for 30 s achieved comparatively higher bacterial reductions of 5.3 log and 4.6 log CFU/g on blueberry skin and agar matrix surfaces, respectively, than 4.5 log and 3.4 log CFU/g reductions for UV alone (6.0 mW/cm). Total phenolic and total anthocyanin contents of fruits were significantly increased after both UV-TiO and UV treatments, compared with water washed control fruits. UV-TiO photocatalysis technology is a non-chemical and residue-free method with reduced water usage for surface disinfection of fresh blueberries.
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http://dx.doi.org/10.1016/j.fm.2018.07.015DOI Listing
December 2018

3D profiling of rough silicon carbide surfaces by coherence scanning interferometry using a femtosecond laser.

Appl Opt 2018 Apr;57(10):2584-2589

We test an erbium-doped fiber femtosecond laser for its potential as a light source for a coherence scanning interferometer for large field-of-view profiling of rough silicon carbide (SiC) surfaces. This infrared fiber pulse laser is able to provide a relatively long temporal coherence length of ∼30   to be appropriate for coherence scanning of rough surfaces. At the same time, it offers a high degree of spatial coherence comparable to that of a monochromatic continuous wave laser to achieve a large measurement field of view. In addition, the highly maintained linear polarization of the pulse laser source permits overcoming the low specular reflectance of rough SiC surfaces by polarization-based optical power splitting control between the reference and measurement arms.
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http://dx.doi.org/10.1364/AO.57.002584DOI Listing
April 2018

Assembly of Complex Macrocycles by Incrementally Amalgamating Unprotected Peptides with a Designed Four-Armed Insert.

J Org Chem 2018 03 7;83(6):3090-3108. Epub 2018 Mar 7.

Department of Chemistry and Biochemistry , University of California Los Angeles , Los Angeles , California 90095 , United States.

We describe the asymmetric synthesis of a highly substituted ω-octynoic acid derivative and demonstrate its utility for generating complex macrocycles from unprotected peptides. The molecule harbors an isolated quaternary center that displays four uniquely functionalized arms, each of which can be reacted orthogonally in sequence as the molecule is integrated into peptide structure. These processing sequences entail (1) scaffold ligation, (2) macrocyclization via internal aromatic alkylations or catalyzed etherifications, (3) acyliminium ion mediated embedding of condensed heterocycles, and (4) terminal alkyne derivatization or dimerization reactions. Numerous polycycles are prepared and fully characterized in this study. Factors that influence reaction efficiencies and selectivity are also probed. We construct a novel mimic of the second mitochondria derived activator of caspase using these techniques, wherein subtle variations in macrocycle connectivity have a marked impact on performance. In general, the chemistry is an important step toward facile, systematic access to complex peptidomimetics synthesized by directly altering the structure and properties of machine-made oligomers.
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http://dx.doi.org/10.1021/acs.joc.7b02958DOI Listing
March 2018

Influence of water and enzyme SpnF on the dynamics and energetics of the ambimodal [6+4]/[4+2] cycloaddition.

Proc Natl Acad Sci U S A 2018 01 18;115(5):E848-E855. Epub 2018 Jan 18.

Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095-1569;

SpnF is the first monofunctional Diels-Alder/[6+4]-ase that catalyzes a reaction leading to both Diels-Alder and [6+4] adducts through a single transition state. The environment-perturbed transition-state sampling method has been developed to calculate free energies, kinetic isotope effects, and quasi-classical reaction trajectories of enzyme-catalyzed reactions and the uncatalyzed reaction in water. Energetics calculated in this way reproduce the experiment and show that the normal Diels-Alder transition state is stabilized by H bonds with water molecules, while the ambimodal transition state is favored in the enzyme SpnF by both intramolecular hydrogen bonding and hydrophobic binding. Molecular dynamics simulations show that trajectories passing through the ambimodal transition state bifurcate to the [6+4] adduct and the Diels-Alder adduct with a ratio of 1:1 in the gas phase, 1:1.6 in water, and 1:11 in the enzyme. This example shows how an enzyme acts on a vibrational time scale to steer post-transition state trajectories toward the Diels-Alder adduct.
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http://dx.doi.org/10.1073/pnas.1719368115DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5798381PMC
January 2018

Asymmetric Synthesis of (-)-6'-β-Fluoro-aristeromycin via Stereoselective Electrophilic Fluorination.

Org Lett 2017 11;19(21):5732-5735

Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University , Seoul, 151-742, Korea.

(-)-6'-β-Fluoro-aristeromycin (2), a potent inhibitor of S-adenosylhomocysteine (AdoHcy) hydrolase, has been synthesized via stereoselective electrophilic fluorination followed by a purine base build-up approach. Interestingly, purine base condensation using a cyclic sulfate resulted in a synthesis of (+)-5'-β-fluoro-isoaristeromycin (2a). Computational analysis indicates that the fluorine atom controlled the regioselectivity of the purine base substitution.
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http://dx.doi.org/10.1021/acs.orglett.7b02470DOI Listing
November 2017

Molecular Dynamics Simulations of Selective Metabolite Transport across the Propanediol Bacterial Microcompartment Shell.

J Phys Chem B 2017 08 22;121(34):8149-8154. Epub 2017 Aug 22.

Department of Chemistry and Biochemistry, University of California, Los Angeles , Los Angeles, California 90095, United States.

Bacterial microcompartments are giant protein-based organelles that encapsulate special metabolic pathways in diverse bacteria. Structural and genetic studies indicate that metabolic substrates enter these microcompartments by passing through the central pores in hexameric assemblies of shell proteins. Limiting the escape of toxic metabolic intermediates created inside the microcompartments would confer a selective advantage for the host organism. Here, we report the first molecular dynamics (MD) simulation studies to analyze small-molecule transport across a microcompartment shell. PduA is a major shell protein in a bacterial microcompartment that metabolizes 1,2-propanediol via a toxic aldehyde intermediate, propionaldehyde. Using both metadynamics and replica-exchange umbrella sampling, we find that the pore of the PduA hexamer has a lower energy barrier for passage of the propanediol substrate compared to the toxic propionaldehyde generated within the microcompartment. The energetic effect is consistent with a lower capacity of a serine side chain, which protrudes into the pore at a point of constriction, to form hydrogen bonds with propionaldehyde relative to the more freely permeable propanediol. The results highlight the importance of molecular diffusion and transport in a new biological context.
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http://dx.doi.org/10.1021/acs.jpcb.7b07232DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5878063PMC
August 2017

Efficacy of aerosolized chlorine dioxide in reducing pathogenic bacteria on washed carrots.

Food Sci Biotechnol 2017 20;26(4):1129-1136. Epub 2017 Jul 20.

1Department of Food Engineering, Mokpo National University, Muan, Jeonnam 58554 Korea.

This study aimed to evaluate the effectiveness of aerosolized chlorine dioxide (ClO) in reducing O157:H7, Typhimurium, and on washed carrots at various time durations and conditions. Populations of the bacteria on carrots were reduced by 1.5, 1.5, and 1.3 log CFU/g, respectively, in each inoculum after exposure to 300 ppm of aerosolized ClO for 30 min. Populations were further reduced by 2.4, 2.3, and 2.1 log CFU/g, respectively, at 400 ppm, showing a positive correlation between the concentrations of ClO and microbial control. The D-value was 13, 14, and 15 min for O157:H7, . Typhimurium, and , respectively. ClO residues were 1 ppm or less in all treated carrots, showing no appearance or discoloration defects. As a result, effectiveness of aerosolized ClO in reducing bacterial pathogens and maintaining the quality of fresh carrots is signifying the prospects of aqueous ClO as a non-thermal disinfectant.
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http://dx.doi.org/10.1007/s10068-017-0139-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6049552PMC
July 2017
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