Prolonged membrane depolarization enhances midbrain dopamine neuron differentiation via epigenetic histone modifications.

He, Xi-Biao,Yi, Sang-Hoon,Rhee, Yong-Hee,Kim, Hyemin,Han, Yong-Mahn,Lee, Suk-Ho,Lee, Hyunsu,Park, Chang-Hwan,Lee, Yong-Sung,Richardson, Eric,Kim, Byung-Woo,Lee, Sang-Hun AlphaMed Press 2011 Stem cells Vol.29 No.11

<P>Understanding midbrain dopamine (DA) neuron differentiation is of importance, because of physiological and clinical implications of this neuronal subtype. We show that prolonged membrane depolarization induced by KCl treatment promotes DA neuron differentiation from neural precursor cells (NPCs) derived from embryonic ventral midbrain (VM). Interestingly, the depolarization-induced increase of DA neuron yields was not abolished by L-type calcium channel blockers, along with no depolarization-mediated change of intracellular calcium level in the VM-derived NPCs (VM-NPCs), suggesting that the depolarization effect is due to a calcium-independent mechanism. Experiments with labeled DA neuron progenitors indicate that membrane depolarization acts at the differentiation fate determination stage and promotes the expression of DA phenotype genes (tyrosine hydroxylase [TH] and DA transporter [DAT]). Recruitment of Nurr1, a transcription factor crucial for midbrain DA neuron development, to the promoter of TH gene was enhanced by depolarization, along with increases of histone 3 acetylation (H3Ac) and trimethylation of histone3 on lysine 4 (H3K4m3), and decreases of H3K9m3 and H3K27m3 in the consensus Nurr1 binding regions of TH promoter. Depolarization stimuli on differentiating VM-NPCs also induced dissociation of methyl CpG binding protein 2 and related repressor complex molecules (repressor element-1 silencing transcription factor corepressor and histone deacetylase 1) from the CpG sites of TH and DAT promoters. Based on these findings, we suggest that membrane depolarization promotes DA neuron differentiation by opening chromatin structures surrounding DA phenotype genes and inhibiting the binding of corepressors, thus allowing transcriptional activators such as Nurr1 to access DA neuron differentiation gene promoter regions.</P>

Characteristics of Ozone Concentration in the Rural Area of Korea

Chung, Yong Seung,Zhong, Liang Xi 한국환경과학회 1995 한국환경과학회지 Vol.4 No.1

Continuous measurements of ground-level ozone (O_3) were made in five minutes intervals in the rural area of Korea from July 1993 to June 1994. This site is located in Chongwon, near latitude 36.4˚ N, longitude 127.6˚ E. The results show that the one-year mean value was 17 ppb, and monthly mean ranged from 6 to 47 ppb. A pronounced maximum in summer and a minimum in winter were found, and these were related to anthropogenic emission and photochemical reaction. Diurnal variations of ozone concentration showed a normal distribution with a maximum at 15:00 - 16:00 and a minimum at 07:00 - 08:00. During the period when ozone concentration was very high (> 80 ppb), the stable winds were from N and NW; on the other hand, when ozone concentration was very low, air movement in the large scale was from the North Pacific Ocean. This suggests that in the rural area the long range transport of anthropogenic pollutants from distant sources can contribute to the larger contribution than the generation of ozone from local sources in the rural area.

대중화권 주식시장 사이의 동태적 상관관계 분석

둥시융 ( Xi Yong Dong ),윤성민 ( Seong Min Yoon ) 국제지역학회 2015 국제지역연구 Vol.19 No.4

본 연구의 목적은 대중화권 주식시장들 사이의 동태적 상관관계를 DCC-GARCH 모형과 2000년 1월 4일부터 2015년 3월 5일까지 일별 자료를 이용하여 추정하고 그것의 분석결과로부터 정책적 시사점을 얻는 것이다. 본 연구의 실증분석에서 얻은 주요 결과를 요약하면 아래와 같다. 첫째, 상해주식시장과 심천주식시장 사이의 동조화 경향이 가장 강하게 나타나고, 금융위기 전후에 그 경향이 그다지 변하지 않은 것으로 나타났다. 둘째, 홍콩주식시장과 대만 주식시장 사이의 동조화 경향이 상대적으로 크게 나타나고, 금융위기 이후에 그 경향이 더 강화되는 것으로 나타났다. 셋째, 중국 대륙 두 주식시장과 홍콩 및 대만 주식시장 사이의 동조화 경향이 상대적으로 크지는 않지만 글로벌 충격을 거치면서 뚜렷하게 강화되고 있는 것으로 나타났다. 본 연구의 분석결과는 정책 입안자, 국제 투자자 및 자산관리자에 대한 몇 가지 중요한 정책적 시사점을 제공할 수 있다. The purpose of this study is to explore the dynamic correlation among the Greater China stock markets for the period January 4, 2000 to March 5, 2015, and to develop policy implications from the results. From the estimation results of the DCC-GARCH model, we found the synchronization between Shanghai and Shenzhen stock markets was the strongest, and it has not changed much before and after the Global Financial Crisis (GFC). Our second finding is that the synchronization between Hong Kong and Taiwan stock markets was relatively large, and it has become stronger after the GFC. The third finding is that the synchronization between Chinese mainland and Hong Kong stock markets, Chinese mainland and Taiwan stock markets were not relatively large, but they have obviously become stronger through the global impact. The findings of this paper have several important implications for policy makers, international investors and portfolio managers.

Soluble expression, purification and the role of C-terminal glycine residues in scorpion toxin BmK AGP-SYPU2

( Rong Zhang ),( Yong Cui ),( Xi Zhang ),( Zhuo Yang ),( Yong Shan Zhao ),( Yong Bo Song ),( Chun Fu Wu ),( Jing Hai Zhang ) 생화학분자생물학회 (구 한국생화학분자생물학회) 2010 BMB Reports Vol.43 No.12

The existence of glycine residues in long-chain scorpion toxins has been well documented. However, their role as analgesics has not been evaluated. To address this issue, we investigated the functional role of glycines in the C-terminal end of Chinese-scorpion toxin from Buthus martensii Karsch (BmK AGP-SYPU2) using site-directed mutagenesis and analgesic activity assays. Recombinant BmK AGP-SYPU2 and its mutants were efficiently expressed in E. coli and purified to homogeneity using immobilized metal ion affinity chromatography (IMAC) and cation exchange chromatography. The mouse-twisting test was used to detect the analgesic activity of BmK AGP-SYPU2 and its mutants. As a result, we identified glycines at the C-terminal end that, when altered, significantly affected analgesic activity. Also, Mut6566 was significantly decreased compared to BmK AGP-SYPU2. These data indicate that the glycines at the C-terminal end are important for the analgesic activity of BmK AGP-SYPU2. [BMB reports 2010; 43(12): 801-806]

Superovulation in Rabbits by Single Injection of FSH Dissolved in Polyvinylpyrrolidone

Choe, Chang-Yong,Kang, Tae-Young,Yin, Xi-Jun,Kang, Da-Won,Ha, Ran-Jo,Lee, Hyo-Jong,Park, Choong-Saeng,Choe, Sang-Yong 한국수정란이식학회 1997 한국수정란이식학회 학술대회 Vol.1997 No.2

Application of N-substituted (aminomethyl)benzoate Strategy in Design of Scutellarein Derivatives with Improved Caco-2 Cell Permeability and In Vitro Antioxidative Activity

Ze-Qin Dai,Hang Su,Min Luo,Yu Ou,Xiao-Zhong Fu,Yong-Xi Dong,Yu-Feng Cha,Shun Zhang,Yong Huang,Yong-Lin Wang 대한화학회 2015 Bulletin of the Korean Chemical Society Vol.36 No.8

A series of 4′-N-substituted (aminomethyl)benzoate derivatives of scutellarein were designed and synthesized. Evaluation of their physiochemical properties showed that the designed target compounds 5a–e exhibit higher chemical stability and aqueous solubility than scutellarin and scutellarein. The permeability (Papp AP to BL ) of 5c–e in Caco-2 cells were 2.8, 8.1, and 12.6 times higher than that of scutellarin and 1.3, 4.1, and 6.0 times higher than that of scutellarein; especially, 5e had the highest P app AP to BL value (7.19 ± 0.31 × 10−6 cm/s) and the lowest ER (P app BL to AP /P app AP to BL ) value of 0.17. In vitro antioxidative evaluation results revealed that 5e could protect against H2O2 -induced PC12 cells’ oxidative damage by attenuating mitochondrial membrane potential loss and decreasing H2O2 -induced reactive oxygen species (ROS) production.

ANNs on Co-occurrence Matrices for Mobile Malware Detection

( Xi Xiao ),( Zhenlong Wang ),( Qi Li ),( Qing Li ),( Yong Jiang ) 한국인터넷정보학회 2015 KSII Transactions on Internet and Information Syst Vol.9 No.7

Android dominates the mobile operating system market, which stimulates the rapid spread of mobile malware. It is quite challenging to detect mobile malware. System call sequence analysis is widely used to identify malware. However, the malware detection accuracy of existing approaches is not satisfactory since they do not consider correlation of system calls in the sequence. In this paper, we propose a new scheme called Artificial Neural Networks (ANNs) on Co-occurrence Matrices Droid (ANNCMDroid), using co-occurrence matrices to mine correlation of system calls. Our key observation is that correlation of system calls is significantly different between malware and benign software, which can be accurately expressed by co-occurrence matrices, and ANNs can effectively identify anomaly in the co-occurrence matrices. Thus at first we calculate co-occurrence matrices from the system call sequences and then convert them into vectors. Finally, these vectors are fed into ANN to detect malware. We demonstrate the effectiveness of ANNCMDroid by real experiments. Experimental results show that only 4 applications among 594 evaluated benign applications are falsely detected as malware, and only 18 applications among 614 evaluated malicious applications are not detected. As a result, ANNCMDroid achieved an F-Score of 0.981878, which is much higher than other methods.

Converting Panax ginseng DNA and chemical fingerprints into two-dimensional barcode

Yong Cai,Peng Li,Xi-Wen Li,Jing Zhao,Hai Chen,Qing Yang,Hao Hu 고려인삼학회 2017 Journal of Ginseng Research Vol.41 No.3

Background: In this study, we investigated how to convert the Panax ginseng DNA sequence code and chemical fingerprints into a two-dimensional code. In order to improve the compression efficiency, GATC2Bytes and digital merger compression algorithms are proposed. Methods: HPLC chemical fingerprint data of 10 groups of P. ginseng from Northeast China and the internal transcribed spacer 2 (ITS2) sequence code as the DNA sequence code were ready for conversion. In order to convert such data into a two-dimensional code, the following six steps were performed: First, the chemical fingerprint characteristic data sets were obtained through the inflection filtering algorithm. Second, precompression processing of such data sets is undertaken. Third, precompression processing was undertaken with the P. ginseng DNA (ITS2) sequence codes. Fourth, the precompressed chemical fingerprint data and the DNA (ITS2) sequence code were combined in accordance with the set data format. Such combined data can be compressed by Zlib, an open source data compression algorithm. Finally, the compressed data generated a two-dimensional code called a quick response code (QR code). Results: Through the abovementioned converting process, it can be found that the number of bytes needed for storing P. ginseng chemical fingerprints and its DNA (ITS2) sequence code can be greatly reduced. After GTCA2Bytes algorithm processing, the ITS2 compression rate reaches 75% and the chemical fingerprint compression rate exceeds 99.65% via filtration and digital merger compression algorithm processing. Therefore, the overall compression ratio even exceeds 99.36%. The capacity of the formed QR code is around 0.5k, which can easily and successfully be read and identified by any smartphone. Conclusion: P. ginseng chemical fingerprints and its DNA (ITS2) sequence code can form a QR code after data processing, and therefore the QR code can be a perfect carrier of the authenticity and quality of P. ginseng information. This study provides a theoretical basis for the development of a quality traceability system of traditional Chinese medicine based on a two-dimensional code.

SysPIMP: the web-based systematical platform for identifying human disease-related mutated sequences from mass spectrometry

Xi, Hong,Park, Jongsun,Ding, Guohui,Lee, Yong-Hwan,Li, Yixue Oxford University Press 2009 Nucleic acids research Vol.37 No.1

<P>Some mutations resulting in protein sequence change might be tightly related to certain human diseases by affecting its roles, such as sickle cell anemia. Until now several databases, such as PMD, OMIM and HGMD, have been developed, providing useful information about human disease-related mutation. Tandem mass spectrometry (MS) has been used for characterizing proteins in various conditions; however, there is no system in place for finding disease-related mutated proteins within the MS results. Here, a Systematical Platform for Identifying Mutated Proteins (SysPIMP; http://pimp.starflr.info/) was developed to efficiently identify human disease-related mutated proteins within MS results. SysPIMP comprises of three layers: (i) a standardized data warehouse, (ii) a pipeline layer for maintaining human disease databases and X!Tandem and BLAST and (iii) a web-based interface. From OMIM AV part, PMD and SwissProt databases, 35 497 non-redundant human disease-related mutated sequences were collected with disease information described by OMIM terms. With the interfaces to browse sequences archived in SysPIMP, X!Tandem, an open source database-search engine used to identify proteins within MS data, was integrated into SysPIMP to help support the detection of potential human disease-related mutants in MS results. In addition, together with non-redundant disease-related mutated sequences, original non-mutated sequences are also provided in SysPIMP for comparative research. Based on this system, SysPIMP will be the platform for efficiently and intensively studying human diseases caused by mutation.</P>

Dynamic response of aluminum honeycomb sandwich panels subjected to hypervelocity impact by porous volcanic rock projectile

Yong Chen,Xi Liu,Chengyue Jiang,Gaojian Liao,Bo Hu 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.6

The dynamic response and damage behavior of aluminum honeycomb sandwich panels (HC/SPs) subjected to hypervelocity impact by volcanic rock projectiles were investigated by hypervelocity impact tests and hydrocode simulations. The experiments were conducted using a two stage light gas gun and the results showed that the failure modes in HC/SPs subjected to hypervelocity impact by volcanic rock projectiles mainly took forms of front-face denting and circular perforation, honeycomb core collapsing and rapture, rear-face petalling and perforation etc. A 3D discrete configuration of the porous volcanic rock projectiles was set up. The hypervelocity impact behavior of the HC/SPs was investigated through hydrocode modeling, within a Lagrange-SPH coupling method in LS-DYNA solver. It was found that the dynamic response and failure modes in the HC/SPs were significantly influenced by the impact location and the impact velocity of the volcanic rock projectile.