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Thickness effect on magnetocrystalline anisotropy of MnPt(0 0 1) film
Qurat-ul-ain,Cuong, Do Duc,Odkhuu, Dorj,Rhim, S.H.,Hong, S.C. Elsevier 2018 Journal of magnetism and magnetic materials Vol.467 No.-
<P><B>Abstract</B></P> <P>We investigated the magnetocrystalline anisotropy (MCA) of MnPt(0 0 1) film and MnPt/MgO(0 0 1) using <I>ab initio</I> electronic structure calculations. We found that the magnetic ground state of the MnPt film strongly depends on thickness (n). In bulk and in film with n ≥ 7 monolayers; AFM-II is the magnetic ground state. However, as the film thickness reduces, the magnetic ground state shifts from AFM-II to AFM-III. We employ layer-by-layer Heisenberg model to explain thickness dependent ground state transition. AFM-III state in the Mn-terminated film shows large perpendicular MCA(PMCA), which further enhances on a MgO(0 0 1) substrate. We conclude that the interface plays a key role for the enhancement of PMCA on the substrate.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Thickness- and surface-termination- dependent MCA of MnPt(0 0 1) film is investigated. </LI> <LI> The Mn-terminated MnPt(0 0 1) film has different magnetic ground state from in bulk when thickness is <7 ML. </LI> <LI> The magnetic structures of the film are studied phenomenologically using rather simplified Heisenberg model. </LI> <LI> The Mn-terminated MnPt(0 0 1) film in AFM-III state shows PMCA when thickness is <9 ML. </LI> <LI> From calculations on MnPt/MgO(0 0 1) it is found that the Mn-O interface enhance PMCA significantly. </LI> </UL> </P>
Ul Ain, Qurrat,Lee, Jong Hwan,Woo, Young Sun,Kim, Yong-Hee Pharmaceutical Society of Korea 2016 Archives of Pharmacal Research Vol.39 No.9
<P>Protein drugs have attracted considerable attention as therapeutic agents due to their diversity and biocompatibility. However, hydrophilic proteins possess difficulty in penetrating lipophilic cell membrane. Although protein transduction domains (PTDs) have shown effectiveness in protein delivery, the importance of selection and position of PTDs in recombinant protein vector constructs has not been investigated. This study intends to investigate the significance of PTD selection and position for therapeutic protein delivery. Heat shock protein 27 (Hsp27) would be a therapeutic protein for the treatment of ischemic heart diseases, but itself is insufficient to prevent systemic degradation and overcoming biochemical barriers during cellular transport. Among all PTD-Hsp27 fusion proteins we cloned, Tat-Hsp27 fusion protein showed the highest efficacy. Nona-arginine (9R) conjugation to the N-terminal of Hsp27 (Hsp27-T) showed higher efficacy than C-terminal. To test the synergistic effect of two PTDs, Tat was inserted to the N-terminal of Hsp27-9R. Tat-Hsp27-9R exhibited enhanced transduction efficiency and significant improvement against oxidative stress and apoptosis. PTD-Hsp27 fusion proteins have strong potential to be developed as therapeutic proteins for the treatment of ischemic heart diseases and selection and position of PTDs for improved efficacy of PTD-fusion proteins need to be optimized considering protein’s nature, transduction efficiency and stability.</P>
Ul Ain, Q.,Chung, H.,Chung, J.Y.,Choi, J.H.,Kim, Y.H. Elsevier Science Publishers 2017 Journal of controlled release Vol.262 No.-
<P>Endothelial dysfunction combined with inflammation leads to atherosclerosis. Endothelium-specific delivery of therapeutic agents at the cellular level-specifically in vivo-is still a difficult task for proper management of atherosclerosis. We designed a redox-sensitive poly(oligo-L-arginine) (rsPOLA) playing dual roles as an endothelium alpha-2 adrenoceptors(alpha-2ARs)-targeted gene carrier and as a substrate for endothelial nitric oxide synthase (eNOS). Overexpression of alpha-2ARs on atherosclerotic endothelial cells was confirmed and the eNOS/rsPOLA nanoplexes following systemic injection demonstrated to 1) enhance eNOS gene delivery into endothelial cells via alpha-2ARs/L-arginine specific binding, 2) increase intracellular level of nitric oxide, 3) suppress inflammatory response in endothelium and finally 4) reduce atherosclerotic plaque in a Ldlr(-/-) atherosclerotic mouse model. Among the tested nanoplexes [ eNOS/rsPOLA, eNOS/{poly(oligo-D-arginine), rsPODA} and eNOS/(racemic mixture, rsRM)], eNOS/rsPOLA reduced atherosclerotic inflammation most effectively as we hypothesized. Current treatment strategy provides strong potential for further development of a gene therapeutic system to ameliorate inflammation and progressive atherosclerotic plaques.</P>
Qurrat ul ain,우영선,정지영,김용희 한국고분자학회 2018 Macromolecular Research Vol.26 No.8
Stem cells secrete many extracellular vesicles such as micro vesicles, exosomes and membrane particles. Exosomes represent characteristics similar to their native cells and exosomes secreted from human mesenchymal stem cells (hMSCs) have demonstrated cardio protective effects. In this study, we examined the synergistic effects of exosomes derived from hMSCs expressing metallothionein (MT), a wellknown therapeutic protein to treat myocardial infarction, for recovery of cell viability in vitro in hypoxic conditions. Tat-metallothionein (Tat-MT) recombinant fusion proteins were prepared by a recombinant method to increase the transduction of metallothionein into exosomes via Tat’s transduction characteristic. Exosomes from hMSCs were transduced with Tat-MT, and characterized by transmission electron microscopy and immunoblotting. Cellular uptake of exosomes and protein was analyzed by confocal microscopy. The cytoprotective effects of exosomes transfected with Tat-MT (Exo/Tat-MT) on cardiomyocytes were evaluated by accessing cell viability. Exo/Tat-MT significantly upregulated cell viability and downregulated apoptosis in cardiomyocytes. The therapeutic potential of exosome-mediated therapeutic protein delivery was demonstrated by strong cell viability (70-80%) under in vitro hypoxic conditions. This study reveals the dual benefits of exosomes derived from hMSCs and highlights a new method of intercellular stem cells mediation for the stem cell-derived treatment of myocardial infarction.
Qurat-ul-ain Sahi,김용수 한국원자력학회 2018 Nuclear Engineering and Technology Vol.50 No.6
In this article, we conducted molecular dynamics simulations to investigate the effect of applied strainand temperature on irradiation-induced damage in alpha-zirconium. Cascade simulations were performedwith primary knock-on atom energies ranging between 1 and 20 KeV, hydrostatic and uniaxialstrain values ranging from 2% (compression) to 2% (tensile), and temperatures ranging from 100 to1000 K. Results demonstrated that the number of defects increased when the displacement cascadeproceeded under tensile uniaxial hydrostatic strain. In contrast, compressive strain states tended todecrease the defect production rate as compared with the reference no-strain condition. The proportionsof vacancy and interstitial clustering increased by approximately 45% and 55% and 25% and 32% for 2%hydrostatic and uniaxial strain systems, respectively, as compared with the unstrained system, whereasboth strain fields resulted in a 15e30% decrease in vacancy and interstitial clustering under compressiveconditions. Tensile strains, specifically hydrostatic strain, tended to produce larger sized vacancy andinterstitial clusters, whereas compressive strain systems did not significantly affect the size of defectclusters as compared with the reference no-strain condition. The influence of the strain system on radiationdamage became more significant at lower temperatures because of less annealing than in highertemperature systems.