140 research outputs found

    Magnetization dynamics induced by in-plane currents in ultrathin magnetic nanostructures

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    Ultrathin magnetic systems have properties qualitatively different from their thicker counterparts, implying that different physics governs their properties. We demonstrate that various such properties can be explained naturally by the Rashba spin-orbit coupling in ultrathin magnetic systems. This work will be valuable for the development of next generation spintronic devices based on ultrathin magnetic systems.Comment: 4+ pages, 3 figure

    Mesenchymal stem cell-derived magnetic extracellular nanovesicles for targeting and treatment of ischemic stroke

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    Exosomes and extracellular nanovesicles (NV) derived from mesenchymal stem cells (MSC) may be used for the treatment of ischemic stroke owing to their multifaceted therapeutic benefits that include the induction of angiogenesis, anti-apoptosis, and anti-inflammation. However, the most serious drawback of using exosomes and NV for ischemic stroke is the poor targeting on the ischemic lesion of brain after systemic administration, thereby yielding a poor therapeutic outcome. In this study, we show that magnetic NV (MNV) derived from iron oxide nanoparticles (IONP)-harboring MSC can drastically improve the ischemic-lesion targeting and the therapeutic outcome. Because IONP stimulated expressions of therapeutic growth factors in the MSC, MNV contained greater amounts of those therapeutic molecules compared to NV derived from naive MSC. Following the systemic injection of MNV into transient middle-cerebral-artery-occlusion (MCAO)-induced rats, the magnetic navigation increased the MNV localization to the ischemic lesion by 5.1 times. The MNV injection and subsequent magnetic navigation promoted the anti-inflammatory response, angiogenesis, and anti-apoptosis in the ischemic brain lesion, thereby yielding a considerably decreased infarction volume and improved motor function. Overall, the proposed MNV approach may overcome the major drawback of the conventional MSC-exosome therapy or NV therapy for the treatment of ischemic stroke.

    Enzymatic properties of the Caenorhabditis elegans Dna2 endonuclease/helicase and a species-specific interaction between RPA and Dna2

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    In both budding and fission yeasts, a null mutation of the DNA2 gene is lethal. In contrast, a null mutation of Caenorhabditis elegans dna2(+) causes a delayed lethality, allowing survival of some mutant C.elegans adults to F2 generation. In order to understand reasons for this difference in requirement of Dna2 between these organisms, we examined the enzymatic properties of the recombinant C.elegans Dna2 (CeDna2) and its interaction with replication-protein A (RPA) from various sources. Like budding yeast Dna2, CeDna2 possesses DNA-dependent ATPase, helicase and endonuclease activities. The specific activities of both ATPase and endonuclease activities of the CeDna2 were considerably higher than the yeast Dna2 (∼10- and 20-fold, respectively). CeDna2 endonuclease efficiently degraded a short 5′ single-stranded DNA tail (<10 nt) that was hardly cleaved by ScDna2. Both endonuclease and helicase activities of CeDna2 were stimulated by CeRPA, but not by human or yeast RPA, demonstrating a species-specific interaction between Dna2 and RPA. These and other enzymatic properties of CeDna2 described in this paper may shed light on the observation that C.elegans is less stringently dependent on Dna2 for its viability than Saccharomyces cerevisiae. We propose that flaps generated by DNA polymerase δ-mediated displacement DNA synthesis are mostly short in C.elegans eukaryotes, and hence less dependent on Dna2 for viability

    Association of the programmed cell death 1 (PDCD1) gene polymorphism with ankylosing spondylitis in the Korean population

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    The PD-1 (programmed death 1) molecule is a negative regulator of T cells. PDCD1 (programmed cell death 1) has been reported to have a genetic association in systemic lupus erythematosus and rheumatoid arthritis in Caucasians. However, there are no reports on the association between this gene and ankylosing spondylitis (AS). The present study investigated the association of the PD-1 polymorphisms and the haplotypes with AS in a Korean population sample. In a case-control association study, two single-nucleotide polymorphisms, PD-1.5 C/T and PD-1.9 T/C, were genotyped in 95 AS patients and 130 healthy controls. The T allele of the PD-1.9 polymorphism was more frequent in the Korean male population with AS than in the Korean male controls (21.0% versus 6.9%, odds ratio 1.89, 95% confidence interval 1.483 to 2.408). The frequency of the CT haplotype (PD-1.5 C/T and PD-1.9 T/C) was higher in the AS patients (19%) than the controls (5.4%) (odds ratio 1.83, 95% confidence interval 1.559 to 2.521). The PD-1 polymorphism was demonstrated in Korean AS patients. The results suggest a genetic association between the PD-1 polymorphism and susceptibility to AS

    Triplet host engineering for triplet exciton management in phosphorescent organic light-emitting diodes

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    The device performances of green phosphorescent organic light-emitting diodes with a triplet mixed host emitting layer were correlated with the energy levels and composition of the host materials. Two hole-transport-type host materials, (4,4-N,N -dicarbazole)biphenyl (CBP) and 4,4 ,4 - tris(N-carbazolyl)triphenylamine (TCTA), were combined with two electron-transport-type host materials, 1,3,5-tris(N-phenylbenzimidazole-2-yl)benzene (TPBI) and PH1. The maximum quantum efficiency was obtained in the 5:5 mixed host in the case of TCTA:TPBI and TCTA:PH1, while CBP:PH1 showed the best performances in the 9:1 mixed host. The quantum efficiency of the green mixed host devices was improved by more than 50% compared with that of the corresponding single host devices.Grant No. RTI04-01-02 from the Regional Technology Innovation Program of the Ministry of Commerce, Industry and Energy (MOCIE

    Anti-inflammatory effects of Radix Gentianae Macrophyllae (Qinjiao), Rhizoma Coptidis (Huanglian) and Citri Unshiu Pericarpium (Wenzhou migan) in animal models

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    <p>Abstract</p> <p>Background</p> <p>KHU14, an ethanolic extract of <it>Radix Gentianae Macrophyllae </it>(<it>Qinjiao</it>), <it>Rhizoma Coptidis </it>(<it>Huanglian</it>) and <it>Citri Unshiu Pericarpium </it>(<it>Wenzhou migan</it>) was tested for its anti-inflammatory effects.</p> <p>Methods</p> <p>Three out of 20 herbs were found to have anti-inflammatory effects. The formulation of these herbs, i.e. KHU14 was tested for croton oil-induced ear edema, carrageenan-induced paw edema, acetic acid-induced capillary permeability, cotton pellet and delayed type hypersensitivity.</p> <p>Results</p> <p>KHU14 exhibited anti-inflammatory effects in animal models of acute and chronic inflammation. The anti-inflammatory activity of KHU14 observed was comparable to that of celecoxib. KHU14 inhibited the production of NO and PGE<sub>2 </sub>in LPS/IFN-gamma-stimulated peritoneal macrophages, and reduced edema and the amount of infiltrated cells in animal models.</p> <p>Conclusion</p> <p>KHU14 exhibited anti-inflammatory effects as demonstrated in typical immunological tests for anti-inflammation <it>in vitro </it>and <it>in vivo</it>.</p

    Acute and Subacute Stent Thrombosis in a Patient With Clopidogrel Resistance: A Case Report

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    Drug-eluting stents (DES) are considered the treatment of choice for most patients with obstructive coronary artery disease when percutaneous intervention (PCI) is feasible. However, stent thrombosis seems to occur more frequently with DES and occasionally is associated with resistance to anti-platelet drugs. We have experienced a case of recurrent stent thrombosis in a patient with clopidogrel resistance. A 63-year-old female patient suffered from acute myocardial infarction and underwent successful PCI of the left anterior descending coronary artery (LAD) with two DESs. She was found to be hyporesponsive to clopidogrel and was treated with triple anti-platelet therapy (aspirin 100 mg, clopidogrel 75 mg, and cilostazol 200 mg daily). Three days after discharge, she developed chest pain and was again taken to the cardiac catheterization laboratory, where coronary angiography (CAG) showed total occlusion of the mid-LAD where the stent had been placed. After intravenous administration of a glycoprotein IIb/IIIa inhibitor, balloon angioplasty was performed, resulting in Thrombolysis In Myocardial Infarction (TIMI) III antegrade flow. The next day, however, she complained of severe chest pain, and the electrocardiogram showed marked ST-segment elevation in V1-V6, I, and aVL with complete right bundle branch block. Emergent CAG revealed total occlusion of the proximal LAD due to stent thrombosis. She was successfully treated with balloon angioplasty and was discharged with triple anti-platelet therapy

    A functional regulatory variant of MYH3 influences muscle fiber-type composition and intramuscular fat content in pigs

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    Muscle development and lipid accumulation in muscle critically affect meat quality of livestock. However, the genetic factors underlying myofiber-type specification and intramuscular fat (IMF) accumulation remain to be elucidated. Using two independent intercrosses between Western commercial breeds and Korean native pigs (KNPs) and a joint linkage-linkage disequilibrium analysis, we identified a 488.1-kb region on porcine chromosome 12 that affects both reddish meat color (a*) and IMF. In this critical region, only the MYH3 gene, encoding myosin heavy chain 3, was found to be preferentially overexpressed in the skeletal muscle of KNPs. Subsequently, MYH3-transgenic mice demonstrated that this gene controls both myofiber-type specification and adipogenesis in skeletal muscle. We discovered a structural variant in the promotor/regulatory region of MYH3 for which Q allele carriers exhibited significantly higher values of a* and IMF than q allele carriers. Furthermore, chromatin immunoprecipitation and cotransfection assays showed that the structural variant in the 5-flanking region of MYH3 abrogated the binding of the myogenic regulatory factors (MYF5, MYOD, MYOG, and MRF4). The allele distribution of MYH3 among pig populations worldwide indicated that the MYH3 Q allele is of Asian origin and likely predates domestication. In conclusion, we identified a functional regulatory sequence variant in porcine MYH3 that provides novel insights into the genetic basis of the regulation of myofiber type ratios and associated changes in IMF in pigs. The MYH3 variant can play an important role in improving pork quality in current breeding programs

    Superior outcomes of kidney transplantation compared with dialysis An optimal matched analysis of a national population-based cohort study between 2005 and 2008 in Korea

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    Data regarding kidney transplantation (KT) and dialysis outcomes are rare in Asian populations. In the present study, we evaluated the clinical outcomes associated with KT using claims data from the Korean national public health insurance program. Among the 35,418 adult patients with incident dialysis treated between 2005 and 2008 in Korea, 1539 underwent KT. An optimal balanced risk set matching was attempted to compare the transplant group with the control group in terms of the overall survival and major adverse cardiac event-free survival. Before matching, the dialysis group was older and had more comorbidities. After matching, there were no differences in age, sex, dialysis modalities, or comorbidities. Patient survival was significantly better in the transplant group than in the matched control group (P<0.001). In addition, the transplant group showed better major adverse cardiac event-free survival than the dialysis group (P<0.001; hazard ratio, 0.49; 95% confidence interval, 0.32-0.75). Korean patients with incident dialysis who underwent long-term dialysis had significantly more cardiovascular events and higher all-cause mortality rates than those who underwent KT. Thus, KT should be more actively recommended in Korean populations.OAIID:RECH_ACHV_DSTSH_NO:T201619962RECH_ACHV_FG:RR00200001ADJUST_YN:EMP_ID:A079841CITE_RATE:1.206FILENAME:Superior_outcomes_of_kidney_transplantation.14.pdfDEPT_NM:컴퓨터공학부EMAIL:[email protected]_YN:YFILEURL:https://srnd.snu.ac.kr/eXrepEIR/fws/file/91ab95e8-39ce-4d72-8fb3-f6b12c82256d/linkCONFIRM:
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