Subwavelength light focusing using random nanoparticles

Park, Jung-Hoon,Park, Chunghyun,Yu, HyeonSeung,Park, Jimin,Han, Seungyong,Shin, Jonghwa,Ko, Seung Hwan,Nam, Ki Tae,Cho, Yong-Hoon,Park, YongKeun Springer Science and Business Media LLC 2013 Nature photonics Vol.7 No.6

A New Water Oxidation Catalyst: Lithium Manganese Pyrophosphate with Tunable Mn Valency

Park, Jimin,Kim, Hyunah,Jin, Kyoungsuk,Lee, Byung Ju,Park, Yong-Sun,Kim, Hyungsub,Park, Inchul,Yang, Ki Dong,Jeong, Hui-Yun,Kim, Jongsoon,Hong, Koo Tak,Jang, Ho Won,Kang, Kisuk,Nam, Ki Tae American Chemical Society 2014 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.136 No.11

<P>The development of a water oxidation catalyst has been a demanding challenge for the realization of overall water-splitting systems. Although intensive studies have explored the role of Mn element in water oxidation catalysis, it has been difficult to understand whether the catalytic capability originates mainly from either the Mn arrangement or the Mn valency. In this study, to decouple these two factors and to investigate the role of Mn valency on catalysis, we selected a new pyrophosphate-based Mn compound (Li<SUB>2</SUB>MnP<SUB>2</SUB>O<SUB>7</SUB>), which has not been utilized for water oxidation catalysis to date, as a model system. Due to the monophasic behavior of Li<SUB>2</SUB>MnP<SUB>2</SUB>O<SUB>7</SUB> with delithiation, the Mn valency of Li<SUB>2-<I>x</I></SUB>MnP<SUB>2</SUB>O<SUB>7</SUB> (<I>x</I> = 0.3, 0.5, 1) can be controlled with negligible change in the crystal framework (e.g., volume change ∼1%). Moreover, inductively coupled plasma mass spectrometry, X-ray photoelectron spectroscopy, ex-situ X-ray absorption near-edge structure, galvanostatic charging–discharging, and cyclic voltammetry analysis indicate that Li<SUB>2-<I>x</I></SUB>MnP<SUB>2</SUB>O<SUB>7</SUB> (<I>x</I> = 0.3, 0.5, 1) exhibits high catalytic stability without additional delithiation or phase transformation. Notably, we observed that, as the averaged oxidation state of Mn in Li<SUB>2-<I>x</I></SUB>MnP<SUB>2</SUB>O<SUB>7</SUB> increases from 2 to 3, the catalytic performance is enhanced in the series Li<SUB>2</SUB>MnP<SUB>2</SUB>O<SUB>7</SUB> < Li<SUB>1.7</SUB>MnP<SUB>2</SUB>O<SUB>7</SUB> < Li<SUB>1.5</SUB>MnP<SUB>2</SUB>O<SUB>7</SUB> < LiMnP<SUB>2</SUB>O<SUB>7</SUB>. Moreover, Li<SUB>2</SUB>MnP<SUB>2</SUB>O<SUB>7</SUB> itself exhibits superior catalytic performance compared with MnO or MnO<SUB>2</SUB>. Our study provides valuable guidelines for developing an efficient Mn-based catalyst under neutral conditions with controlled Mn valency and atomic arrangement.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2014/jacsat.2014.136.issue-11/ja410223j/production/images/medium/ja-2013-10223j_0012.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja410223j'>ACS Electronic Supporting Info</A></P>

Magnesium Corrosion Triggered Spontaneous Generation of H₂O₂ on Oxidized Titanium for Promoting Angiogenesis

Park, Jimin,Du, Ping,Jeon, Jin‐,Kyung,Jang, Gun Hyuk,Hwang, Mintai Peter,Han, Hyung‐,Seop,Park, Kwideok,Lee, Kwan Hyi,Lee, Jee‐,Wook,Jeon, Hojeong,Kim, Yu‐,Chan,Park, Jong Woon WILEY‐VCH Verlag 2015 Angewandte Chemie Vol.127 No.49

<P><B>Abstract</B></P><P>Although the use of reactive oxygen species (ROS) has been extensively studied, current systems employ external stimuli such as light or electrical energy to produce ROS, which limits their practical usage. In this report, biocompatible metals were used to construct a novel electrochemical system that can spontaneously generate H<SUB>2</SUB>O<SUB>2</SUB> without any external light or voltage. The corrosion of Mg transfers electrons to Au‐decorated oxidized Ti in an energetically favorable process, and the spontaneous generation of H<SUB>2</SUB>O<SUB>2</SUB> in an oxygen reduction reaction was revealed to occur at titanium by combined spectroscopic and electrochemical analyses. The controlled release of H<SUB>2</SUB>O<SUB>2</SUB> noticeably enhanced in vitro angiogenesis even in the absence of growth factors. Finally, a new titanium implant prototype was developed by Mg incorporation, and its potential for promoting angiogenesis was demonstrated.</P>

Wide area illumination Raman scheme for simple and nondestructive discrimination of seawater cultured pearls

Park, Seok Chan,Kim, Minjung,Park, Jimin,Chung, Hoeil,Kim, Hea Yeon John Wiley Sons, Ltd. 2009 JOURNAL OF RAMAN SPECTROSCOPY - Vol.40 No.12

<P>Raman spectroscopy, along with discriminant partial least squares (PLS), was successfully used to discriminate among three different groups of cultured pearls (fresh water, Akoya and South seawater). The discrimination between Akoya and South seawater pearls using XRF (X-ray fluorescence), one of the most frequently adopted analytical methods in pearl analysis, has been especially difficult owing to their similar mineral compositions. The selective Raman features helped in effectively discriminating between these two pearl groups. The difference in the intensities of the CaCO<SUB>3</SUB> bands of Akoya and South seawater pearls provided a valuable clue. Along with the selective Raman feature, a reproducible Raman spectral collection achieved using a wide area illumination (WAI) scheme played an important role in the determination of the pearl groups, although the pearls were hard-surfaced, round, solid samples of different sizes and surface shapes. Unwanted spectral variation originating from sensitivity to sample placement relative to the focal plane and from unsuccessful sample representation due to the probing of a localized area, factors that could possibly deteriorate Raman reproducibility, were substantially lessened using the WAI scheme. ATR (attenuated total reflection) IR spectroscopy requiring direct contact with the pearl could be inadequate for discrimination or classification where large numbers of repeating and reproducible measurements are required. Copyright © 2009 John Wiley & Sons, Ltd.</P> <B>Graphic Abstract</B> <P>The selective Raman features enable to discriminate between two seawater cultured pearl groups. The difference in the intensities of the CaCO<SUB>3</SUB> bands of Akoya and South seawater pearls provided a valuable clue for discrimination. The reproducible spectral collection for hard-surfaced and round pearl samples was achieved using the wide area illumination (WAI) scheme. <img src='wiley_img/03770486-2009-40-12-JRS2401-gra001.gif' alt='wiley_img/03770486-2009-40-12-JRS2401-gra001'> </P>

Genomic alterations in <i>BCL2L1</i> and <i>DLC1</i> contribute to drug sensitivity in gastric cancer

Park, Hansoo,Cho, Sung-Yup,Kim, Hyerim,Na, Deukchae,Han, Jee Yun,Chae, Jeesoo,Park, Changho,Park, Ok-Kyoung,Min, Seoyeon,Kang, Jinjoo,Choi, Boram,Min, Jimin,Kwon, Jee Young,Suh, Yun-Suhk,Kong, Seong-H National Academy of Sciences 2015 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.112 No.40

<P><B>Significance</B></P><P>Gastric cancer (GC) is one of the major causes of cancer-related deaths worldwide, but targeted therapy for GC is limited. Here, we identified two druggable targets from genomic alteration profiling of 103 patients with GC from Asia and validated the target suitability using patient-derived GC xenograft models, which recapitulate the tumor biology observed in patients. Combination therapy of irinotecan (standard treatment) with a <I>BCL2L1</I> (<I>BCL2</I>-like 1)-targeted drug was effective in size reduction of GC tumors having amplification of the <I>BCL2L1</I> gene, and genomic mutations of deleted in liver cancer 1 (<I>DLC1</I>) were associated with increased sensitivity to a ROCK inhibitor. Therefore, our study strongly suggests that <I>BCL2L1</I> and <I>DLC1</I> can serve as targets for novel GC therapies.</P><P>Gastric cancer (GC) is the third leading cause of cancer-related deaths worldwide. Recent high-throughput analyses of genomic alterations revealed several driver genes and altered pathways in GC. However, therapeutic applications from genomic data are limited, largely as a result of the lack of druggable molecular targets and preclinical models for drug selection. To identify new therapeutic targets for GC, we performed array comparative genomic hybridization (aCGH) of DNA from 103 patients with GC for copy number alteration (CNA) analysis, and whole-exome sequencing from 55 GCs from the same patients for mutation profiling. Pathway analysis showed recurrent alterations in the Wnt signaling [<I>APC</I>, <I>CTNNB1</I>, and <I>DLC1</I> (deleted in liver cancer 1)], ErbB signaling (<I>ERBB2</I>, <I>PIK3CA</I>, and <I>KRAS</I>), and p53 signaling/apoptosis [<I>TP53</I> and <I>BCL2L1</I> (BCL2-like 1)] pathways. In 18.4% of GC cases (19/103), amplification of the antiapoptotic gene <I>BCL2L1</I> was observed, and subsequently a <I>BCL2L1</I> inhibitor was shown to markedly decrease cell viability in <I>BCL2L1</I>-amplified cell lines and in similarly altered patient-derived GC xenografts, especially when combined with other chemotherapeutic agents. In 10.9% of cases (6/55), mutations in <I>DLC1</I> were found and were also shown to confer a growth advantage for these cells via activation of Rho-ROCK signaling, rendering these cells more susceptible to a ROCK inhibitor. Taken together, our study implicates <I>BCL2L1</I> and <I>DLC1</I> as potential druggable targets for specific subsets of GC cases.</P>

Label-free bacterial detection using polydiacetylene liposomes

Park, Jimin,Ku, Seul Kathy,Seo, Deokwon,Hur, Kahyun,Jeon, Hojeong,Shvartsman, Dmitry,Seok, Hyun-Kwang,Mooney, David J.,Lee, Kangwon The Royal Society of Chemistry 2016 Chemical communications Vol.52 No.68

<P>Polydiacetylene (PDA) liposomes were prepared to selectively capture target released from bacteria. Specific interplay between released-surfactin and PDA resulted in a conformal change in the structure of PDA, highlighting the potential of indirect interactions between bacteria and PDA in the construction of new label-free bacterial sensors.</P>

The ethanol extract of <i>Zizyphus jujuba var. spinosa</i> seeds ameliorates the memory deficits in Alzheimer's disease model mice

Park, Hye Jin,Jung, In Ho,Kwon, Huiyoung,Yu, Jimin,Jo, Eunbi,Kim, Haneul,Park, Se Jin,Lee, Young Choon,Kim, Dong Hyun,Ryu, Jong Hoon Elsevier Ireland Ltd 2019 Journal of Ethnopharmacology Vol.233 No.-

<P><B>Abstract</B></P> <P><B>Ethnopharmacological relevance</B></P> <P>The seeds of Zizyphus jujuba var. spinosa (Bunge) Hu ex H.F. Chow (Rhamnaceae) have long been treated as hypnotic agent for sleep disturbances in traditional Chinese and Korean medicine and many previous studies have focused on its effect in central nervous system.</P> <P><B>Aims of study</B></P> <P>The present study aimed to provide evidence showing that the ethanol extract of <I>Zizyphus jujuba</I> var. <I>spinosa</I> seeds (EEZS), which may regulate plasmin activity, has the potential to serve as a therapeutic agent for AD.</P> <P><B>Materials and methods</B></P> <P>Synaptic function was determined by measuring long-term potentiation (LTP) in Shaffer-collateral pathway of the hippocampus. Protein levels of plasmin or plasminogen were examined using western blotting. Plasmin activity was measured using ELISA. Cognitive functions were measured using passive avoidance and object recognition tests in the 5XFAD mice.</P> <P><B>Results</B></P> <P>Our <I>in vitro</I> analysis revealed that EEZS-treated hippocampal slices from 5XFAD mice, a mouse model of AD, showed significantly higher long-term potentiation levels than did vehicle-treated hippocampal slices from 5XFAD mice (<I>P</I> < 0.05). Additionally, EEZS significantly elevated the plasmin level and activity in the hippocampal slices from 5XFAD mice (<I>P</I> < 0.05). Co-treating the slices with EEZS and 6-aminocaproic acid, a plasmin inhibitor, blocked the ameliorating effects of EEZS on the synaptic deficits that were present in 5XFAD mice. Compatible with the <I>in vitro</I> study, the results of our <I>in vivo</I> investigation showed that administering EEZS orally to 5XFAD mice ameliorated their memory impairments. Orally administered EEZS also elevated the plasmin level and activity in the hippocampus of 5XFAD mice.</P> <P><B>Conclusions</B></P> <P>Collectively, our findings suggest that EEZS alleviates the AD-like symptoms in 5XFAD mice by regulating of plasmin activity and EEZS may be a suitable treatment for AD.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Pharmacopuncture in Korea: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Park, Jimin,Lee, Hyangsook,Shin, Byung-Cheul,Lee, Myeong Soo,Kim, Boryang,Kim, Jong-In Hindawi Publishing Corporation 2016 Evidence-based Complementary and Alternative Medic Vol.2016 No.-

<P><I>Background</I>. Pharmacopuncture is a new form of acupuncture combining acupuncture with herbal medicine, and it has been used under various conditions in Korea. The aim of this study is to establish clinical evidence for the safety and efficacy of pharmacopuncture in Korea.<I> Methods</I>. We searched 9 databases and two relevant journals up to December 2014 using keywords, such as pharmacopuncture. All randomized, controlled trials evaluating pharmacopuncture under any conditions in Korea were considered.<I> Results</I>. Twenty-nine studies involving 1,211 participants were included. A meta-analysis of two studies on obesity showed that 5 to 8 weeks of pharmacopuncture reduced weight, waist circumference, and body mass index (BMI) more than normal saline injections. In the 5 studies of musculoskeletal conditions, 7 to 30 days of pharmacopuncture had additional effects on the reduction of pain intensity, and this benefit was maintained by limiting analyses to studies with a low risk of bias for randomization and/or allocation concealment.<I> Conclusions</I>. This systematic review suggests the potential of pharmacopuncture for obesity and musculoskeletal diseases. However, it is difficult to recommend pharmacopuncture as an evidence-based treatment because of methodological flaws and small sample sizes of the included studies. Further well-designed trials are needed to draw a definitive conclusion.</P>

General assay for enzymes in the heptose biosynthesis pathways using electrospray ionization mass spectrometry

Park, Jimin,Lee, Daeun,Seo, Eun Kyoung,Ryu, Jae-Sang,Shin, Dong Hae Springer International 2017 Applied microbiology and biotechnology Vol.101 No.11

<P>The ADP-l-glycero-beta-d-manno-heptose and the GDP-6-deoxy-alpha-d-manno-heptose biosynthesis pathways play important roles in constructing lipopolysaccharide of Gram-negative bacteria. Blocking the pathways is lethal or increases antibiotic susceptibility to pathogens. Therefore, the enzymes involved in the pathways are novel antibiotic drug targets. Here, we designed an efficient method to assay the whole enzymes in the pathways using mass spectrometry and screened 148 compounds. One promising lead is (-)-nyasol targeting d-glycero-alpha-d-manno-heptose-1-phosphate guanylyltransferase (HddC) included in the GDP-6-deoxy-alpha-d-manno-heptose biosynthesis pathway from Burkholderia pseudomallei. The inhibitory activity of the lead compound against HddC has been confirmed by blocking the system transferring the guanosine monophosphate (GMP) moiety to alpha-d-glucose-1-phosphate. (-)-Nyasol exhibits the half maximal inhibitory concentration (IC50) value of 17.6 mu M. A further study is going on using (-)-nyasol derivatives to find better leads with high affinity.</P>

Biological Inspiration toward Artificial Photostystem

Jimin Park,Jung-Ho Lee,Yong-Sun Park,Kyoungsuk Jin,Ki Tae Nam 한국진공학회 2013 한국진공학회 학술발표회초록집 Vol.2013 No.8