Ratchet effect of virtual domain wall motion in discrete magnetic nanodot chains

Ma, Xiao-Ping,Kim, Seon-Dae,Piao, Hong-Guang,Kim, Dong-Hyun JAPAN SOCIETY OF APPLIED PHYSICS 2017 Applied physics express Vol.10 No.12

Field-controllable injection of virtual magnetic domainwall in discrete magnetic nanodot chains

Xiao-Ping Ma,김선대,PIAO HONGGUANG,김동현 한국물리학회 2018 Current Applied Physics Vol.18 No.1

Periodic injection behaviors of virtual magnetic domain wall (VDW) have been systematically investigated in asymmetrically shaped nanodot chains by means of micromagnetic simulations. Systematic investigation on a controllable VDW injection has been carried out. We demonstrate that precise control of VDW injection is achievable by using different nanodot shapes as well as by changing alternating magnetic field (AC field) profiles. The VDW position can be tuned by adjusting AC field frequency and amplitude. Field-controllable periodic VDW injection phenomenon is found to be sustainable over wide ranges of phase diagram spanned by AC field frequency and amplitude.

Position-dependent Spontaneous Motion of the Magnetic Domain Wall in Ferromagnetic Nanowires

Xiao-Ping Ma,Hong-Guang Piao,심제호,주하나 데데,김동현 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.62 No.2

We have investigated the dependence of the spontaneous dynamics of the magnetic domain wall in ferromagnetic nanowires on the initial position of the domain wall without any external field. Using micromagnetic simulations, we have observed in detail a spontaneous magnetic domain wall motion for various wire widths and thicknesses. We have found that the average speed of the spontaneous domain wall motion significantly depends on the wire width and thickness, as well as the starting position of the domain wall motion. We conclude that the spontaneous magnetic domain wall motion should be considered very carefully in practical design of spintronic devices based on magnetic domain wall motion.

Meta-analysis of Circulating Tumor Cells as a Prognostic Marker in Lung Cancer

Ma, Xue-Lei,Xiao, Zhi-Lan,Liu, Lei,Liu, Xiao-Xiao,Nie, Wen,Li, Ping,Chen, Nian-Yong,Wei, Yu-Quan Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.4

Introduction: Recent studies have shown that circulating tumor cells (CTCs) play potential roles as diagnostic and prognostic biomarkers with various cancer types. The aim of this study was to comprehensively and quantitatively summarize the evidence for the use of CTCs to predict the survival outcome of lung cancer patients. Materials and Methods: Relevant literature was identified using Medline and EMBASE. Patients' clinical characteristics, overall survival (OS) and progression-free survival (PFS) together with CTC positive rates at different time points (before, during and after treatment) were extracted. A meta-analysis was performed to clarify the prognostic role of CTCs and the correlation between the CTC appearance and clinical characteristics. Results: A total of 12 articles containing survival outcomes and clinical characteristics and 15 articles containing only clinical characteristics were included for the global meta-analysis. The hazard ratio (HR) for OS predicted by pro-treatment CTCs was 2.61 [1.82, 3.74], while the HR for PFS was 2.37 [1.41, 3.99]. The HR for OS predicted by post-treatment CTCs was 4.19 [2.92, 6.00], while the HR for PFS was 4.97 [3.05, 8.11]. Subgroup analyses were conducted according to histological classification and detection method. Odds ratio (OR) showed the appearance of pro-treatment CTCs correlated with the lymph node status, distant metastasis, and TNM staging, while post-treatment CTCs correlated with TNM staging only. Conclusion: Detection of CTCs in the peripheral blood indicates a poor prognosis in patients with lung cancer.

Suppression of Walker breakdown in gapped magnetic nanowires

Ma, Xiao-Ping,Kim, Seon-Dae,Park, Seung-Young,Choi, Yeon Suk,Piao, Hong-Guang,Kim, Dong-Hyun American Institute of Physics 2018 Journal of Applied Physics Vol.124 No.8

Molecular cloning and characterization of two novel DREB genes encoding dehydration-responsive element binding proteins in halophyte Suaeda salsa

Xiao-Bo Sun,Hong-Xiang Ma,Xin-Ping Jia,Yu Chen,Xiao-Qing Ye 한국유전학회 2015 Genes & Genomics Vol.37 No.2

The dehydration-responsive element-binding(DREB) proteins play an important role in regulatingexpression of stress-inducible genes under abiotic stresses. In this study, two genes encoding putative DREB proteins,named SsDREBa and SsDREBb, were cloned from halophyteSuaeda salsa L. using RACE method. The deducedSsDREBa and SsDREBb proteins contain a typical AP2/ERF domain. Multiple sequence alignments and phylogeneticanalysis revealed that the two SsDREB genes of S. salsa were highly similar in AP2/ERF domains at thenucleotide and amino acid levels and belong to the A-6subgroup of the DREB transcription factor subfamily. Asubcellular localization assay showed that both SsDREBslocalized to the nucleus. Yeast one-hybrid experimentstestified that both proteins were able to specifically bind tothe DRE sequence and activate the expression of the downstreamHIS reporter gene in yeast. Quantitative real-timePCR analysis demonstrated that under normal conditions,the expression level of SsDREBa was the most high in theroots and no SsDREBa mRNAs were detected in the stems;SsDREBb expressed at relatively higher levels in the leavesthan in the roots and stems. The expression of SsDREa andSsDREBb genes in S. salsa roots and leaves was remarkablyinduced by high-salt and dehydration treatments, butnot by cold and ABA, and exhibited stronger induction inroots and leaves, respectively. These results indicate thatthe SsDREBa and SsDREBb are novel stress-responsivetranscription factors, which are involved in the drought andhigh-salt stress responses through ABA-independent pathwaysand could be used for production of stress-toleranttransgenic crops.

Development and validation of reactor nuclear design code CORCA-3D

Ping An,Yongqiang Ma,Peng Xiao,Fengchen Guo,Wei Lu,Xiaoming Chai 한국원자력학회 2019 Nuclear Engineering and Technology Vol.51 No.7

The advanced node core code CORCA-3D is one of the independent developed codes of NPIC for the nuclear reactor core design. CORCA-3D code can calculate the few-group cross section, solve the 3D diffusion equations, consider the thermal-hydraulic feedback, reconstruct the pin-by-pin power. It has lots of functions such as changing core status calculation, critical searching, control rod value calculation, coefficient calculation and so on. The main theory and functions of CORCA-3D code are introduced and validated with a lot of reactor measured data and the SCIENCE system. Now, CORCA-3D code has been applied in ACP type reactor nuclear cores design.

Covalent Immobilization of Penicillin G Acylase onto Fe₃O₄@Chitosan Magnetic Nanoparticles

( Xiao Min Ling ),( Xiang Yu Wang ),( Ping Ma ),( Yi Yang ),( Jie Mei Qin ),( Xue Jun Zhang ),( Ye Wang Zhang ) 한국미생물 · 생명공학회 2016 Journal of microbiology and biotechnology Vol.26 No.5

Penicillin G acylase (PGA) was immobilized on magnetic Fe₃O₄@chitosan nanoparticles through the Schiff base reaction. The immobilization conditions were optimized as follows: enzyme/support 8.8 mg/g, pH 6.0, time 40 min, and temperature 25℃. Under these conditions, a high immobilization efficiency of 75% and a protein loading of 6.2 mg/g-support were obtained. Broader working pH and higher thermostability were achieved by the immobilization. In addition, the immobilized PGA retained 75% initial activity after ten cycles. Kinetic parameters Vmax and Km of the free and immobilized PGAs were determined as 0.113 mmol/min/mg-protein and 0.059 mmol/min/mg-protein, and 0.68 mM and 1.19 mM, respectively. Synthesis of amoxicillin with the immobilized PGA was carried out in 40% ethylene glycol at 25℃ and a conversion of 72% was obtained. These results showed that the immobilization of PGA onto magnetic chitosan nanoparticles is an efficient and simple way for preparation of stable PGA.

Astragaloside IV Prevents Obesity-Associated Hypertension by Improving Pro-Inflammatory Reaction and Leptin Resistance

Ping Jiang,Dufang Ma,Xue Wang,Yongcheng Wang,Yuxin Bi,Jinlong Yang,Xuebing Wang,Xiao Li 한국분자세포생물학회 2018 Molecules and cells Vol.41 No.3

Low-grade pro-inflammatory state and leptin resistance are important underlying mechanisms that contribute to obesityassociated hypertension. We tested the hypothesis that Astragaloside IV (As IV), known to counteract obesity and hypertension, could prevent obesity-associated hypertension by inhibiting pro-inflammatory reaction and leptin resistance. High-fat diet (HFD) induced obese rats were randomly assigned to three groups: the HFD control group (HF con group), As IV group, and the As IV + α-bungaratoxin (α-BGT) group (As IV+α-BGT group). As IV (20 mg·Kg-1·d-1) was administrated to rats for 6 weeks via daily oral gavage. Body weight and blood pressure were continuously measured, and NE levels in the plasma and renal cortex was evaluated to reflect the sympathetic activity. The expressions of leptin receptor (LepRb) mRNA, phosphorylated signal transducer and activator of transcription-3 (p-STAT3), phosphorylated phosphatidylinositol 3-kinase (p-PI3K), suppressor of cytokine signaling 3 (SOCS3) mRNA, and protein-tyrosine phosphatase 1B (PTP1B) mRNA, pro-opiomelanocortin (POMC) mRNA and neuropeptide Y (NPY) mRNA were measured by Western blot or qRT-PCR to evaluate the hypothalamic leptin sensitivity. Additionally, we measured the protein or mRNA levels of α7nAChR, inhibitor of nuclear factor κB kinase subunit β/nuclear factor κB (IKKβ/NF-KB) and pro-inflammatory cytokines (IL-1β and TNF-α) in hypothalamus and adipose tissue to reflect the anti-inflammatory effects of As IV through upregulating expression of α7nAChR. We found that As IV prevented body weight gain and adipose accumulation, and also improved metabolic disorders in HFD rats. Furthermore, As IV decreased BP and HR, as well as NE levels in blood and renal tissue. In the hypothalamus, As IV alleviated leptin resistance as evidenced by the increased p-STAT3, LepRb mRNA and POMC mRNA, and decreased p-PI3K, SOCS3 mRNA, and PTP1B mRNA. The effects of As IV on leptin sensitivity were related in part to the up-regulated α7nAchR and suppressed IKKβ/NF-KB signaling and pro-inflammatory cytokines in the hypothalamus and adipose tissue, since co-administration of α7nAChR selective antagonist α-BGT could weaken the improved effect of As IV on central leptin resistance. Our study suggested that As IV could efficiently prevent obesityassociated hypertension through inhibiting inflammatory reaction and improving leptin resistance; furthermore, these effects of As IV was partly related to the increased α7nAchR expression.

MTHFR C677T Polymorphism and Ovarian Cancer Risk: A Meta-analysis

Ding, Xiao-Ping,Feng, Li,Ma, Li Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.8

Background: Many studies have investigated possible association between the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and ovarian cancer risk, but the impact is still unclear owing to the obvious inconsistencies. This study was performed to quantify the strength of the association with a metaanalysis. Methods: We searched the PubMed, Embase, and CNKI databases for studies relating the association between MTHFR C677T polymorphism and ovarian cancer risk and estimated summary odds ratios (ORs) with confidence intervals (CIs) for assessment. Results: Finally, eight studies with a total of 3,379 ovarian cancer cases and 4,078 controls were included into this meta-analysis. Overall the showed that MTHFR C677T polymorphism was not associated with ovarian cancer risk under all genetic models ($OR_{T\;versus\;C}$ = 1.03, 95%CI 0.90-1.18; $OR_{TT\;versus\;CC}$ = 1.08, 95%CI 0.79-1.47; $OR_{TT\;versus\;TC+CC}$ = 1.05, 95%CI 0.80-1.37; $OR_{TT+TC\;versus\;CC}$ = 1.05, 95%CI 0.86-1.21). Meta-analyses of studies with confirmation of HWE also showed no significant association. Subgroup analyses by ethnicity showed there was no significant association in the Caucasians but MTHFR C677T polymorphic variant T contributed to increased risk of ovarian cancer in East Asians. No evidence of publication bias was observed. Conclusion: Meta-analyses of available data show that MTHFR C677T polymorphism is not associated with ovarian cancer risk in Caucasians, but the MTHFR polymorphic variant T may contribute to increased risk in East Asians.