Targeted and controlled drug delivery system loading artersunate for effective chemotherapy on CD44 overexpressing cancer cells

Tran, T. H.,Nguyen, T. D.,Nguyen, H.,Nguyen, H. T.,Kim, J. O.,Yong, C. S.,Nguyen, C. N. Springer Science + Business Media 2016 Archives of Pharmacal Research Vol.39 No.5

<P>Poly(d,l-lactic-co-glycolic acid) (PLGA) nanoparticles with negative surface charge were reversed to positive by cationic surfactant-DDAB before being coated with an anionic polymer, hyaluronic acid, to improve their site-specific intracellular delivery against CD44 receptor overexpressing cancer cells. Incorporating artesunate (ART)-a promising anticancer drug into PLGA/HA nanoparticles, is expected not only to overcome its poor aqueous solubility and stability but also enhance the activities. The obtained particles were characterized by dynamic light scattering, zeta potential measurements, and transmission electron microscopy (TEM). Cancer cell internalization of the NPs was evaluated by flow cytometry and cytotoxicity of the NPs was tested by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide assay. PLGA/HA nanoparticles showed greater extent of cellular uptake to SCC-7 and MCF-7 cells, indicating their affinity with CD44 receptor-mediated endocytosis. Almost 60 % of ART was released into the outer media after 48 h. In vitro fluorescence sorting demonstrated that PLGA/HA had highly efficient targeting and accumulation into CD44 receptor overexpression cells. The significant reduction in cell viability as well as greater induction of apoptosis suggested a potential in anticancer therapy of ART loaded PLGA/HA.</P>

Design and Implementation of Hybrid Multilevel Inverters

T.V. Tran,J.R. Ahn,T.W. Chun,H.H. Lee,H.G. Kim,D.W.Yoo 전력전자학회 2009 전력전자학술대회 논문집 Vol.2009 No.1

Hybrid and cascade multilevel inverter topology has presented a modern trend for reducing the power circuits of multilevel inverter in applications. A proper PWM control technique can maximize voltage range and obtain a PWM performance similar to that in conventional multilevel inverters. This paper will present a simple carrier PWM control technique for controlling the hybrid 5-level inverter, which consists of two-level and H-bridge inverter in series. While common sinusoidal PWM methods can produce only a limited voltage, the novel carrier PWM can extend the voltage at the largest range. Simulation and experimental results have been implemented to demonstrate the proposed PWM method.

An Effective Route to Control the Magnetic-Phase Transition and Magnetocaloric Effect of La_0.7Ca_0.3MnO₃ Nanoparticles

Phan, T. L.,Thanh, T. D.,Ho, T. A.,Manh, T. V.,Tran, Q. T.,Lampen, P.,Phan, M. H.,Yu, S. C. IEEE 2014 IEEE transactions on magnetics Vol.50 No.11

<P>This paper points out that the magnetic-phase transition and magnetocaloric effect of La<SUB>0.7</SUB>Ca<SUB>0.3</SUB>MnO<SUB>3</SUB> (LCMO) can be easily controlled by using the mechanical milling method. Changing the milling time from 5 to 30 min, we have obtained LCMO nanoparticles (NPs) with average crystallite sizes (d, determined by the Williamson-Hall method) ranging from 100 to 45 nm. The magnetic studies (based on a superconducting quantum interference device) and simple analyses (based on Banerjee's criteria) prove the magnetic-phase transformation from the first-order to the second-order, which takes place at a threshold value of d located in the range 60-70 nm. Compared with the as-prepared LCMO sample (a first-order magnetic phase transition), though the d decrease reduces the values of the T<SUB>C</SUB>, magnetization, magnetic-entropy change, and refrigerant capacity, but the width of the magnetic phase transition is increased remarkably. This widens the working range of LCMO NPs in magnetic refrigeration applications. We believe that the presence of surface-related effects, lattice strain, and distortions leads to Mn<SUP>3+</SUP>-Mn<SUP>4+</SUP> ferromagnetic interactions in LCMO NPs weaker than that in the as-prepared sample.</P>

Graphene, MoS<SUB>2</SUB> and h-BN 단일층의 마모 특성에 관한 비교 연구

쩐반띠엔(T. Tran),Phat Ngoc Huynh,정구현(K.H. Chung) 한국정밀공학회 2018 한국정밀공학회 학술발표대회 논문집 Vol.2018 No.5월

Synthesis of nitrogen doped graphite oxide and its electrochemical properties

Ra, E.J.,Tran, M.H.,Yang, S.,Kim, T.H.,Yang, C.S.,Chung, Y.J.,Lee, Y.K.,Kim, I.J.,Jeong, H.K. Elsevier 2014 CURRENT APPLIED PHYSICS Vol.14 No.1

We herein report a synthesis nitrogen-doped graphite oxide (N-doped GO) by heat treatment with melamine. The N-doped GO contains 4 at % of nitrogen, incurring the oxygen reduction reaction by nitrogen functional groups. Two kinds of aqueous electrolytes are used for finding the electrocatalytic activities, resulting in symmetric oxygen reduction reaction peaks at -0.8 and 0 V in 6 M KOH and 1 M H<SUB>2</SUB>SO<SUB>4</SUB> electrolytes, respectively. The N-doped GO is more activated in the acid electrolyte compared to thermally reduced graphite oxide (TrGO). Specific volumetric capacitance of N-doped GO in 1.8 M tetraethylmethylammonium tetrafluoroborate electrolyte is 57.4 F cc<SUP>-1</SUP> which is higher than 30.5 F cc<SUP>-1</SUP> of the TrGO, demonstrating positive effects of the nitrogen doping in the organic electrolytes for the energy storage devices.

Ceruloplasmin is an endogenous protectant against kainate neurotoxicity

Shin, E.J.,Jeong, J.H.,Chung, C.K.,Kim, D.J.,Wie, M.B.,Park, E.S.,Chung, Y.H.,Nam, Y.,Tran, T.V.,Lee, S.Y.,Kim, H.J.,Ong, W.Y.,Kim, H.C. Pergamon ; Elsevier Science Ltd 2015 FREE RADICAL BIOLOGY AND MEDICINE Vol.84 No.-

To determine the role of ceruloplasmin (Cp) in epileptic seizures, we used a kainate (KA) seizure animal model and examined hippocampal samples from epileptic patients. Treatment with KA resulted in a time-dependent decrease in Cp protein expression in the hippocampus of rats. Cp-positive cells were colocalized with neurons or reactive astrocytes in KA-treated rats and epileptic patient samples. KA-induced seizures, initial oxidative stress (i.e., hydroxyl radical formation, lipid peroxidation, protein oxidation, and synaptosomal reactive oxygen species), altered iron status (increasing Fe<SUP>2+</SUP> accumulation and L-ferritin-positive reactive microglial cells and decreasing H-ferritin-positive neurons), and impaired glutathione homeostasis and neurodegeneration (i.e., Fluoro-Nissl and Fluoro-Jade B staining analyses) were more pronounced in Cp antisense oligonucleotide (ASO)- than in Cp sense oligonucleotide-treated rats. Consistently, Cp ASO facilitated KA-induced lactate dehydrogenase (LDH) release, Fe<SUP>2+</SUP> accumulation, and glutathione loss in neuron-rich and mixed cultures. However, Cp ASO did not alter KA-induced LDH release or Fe<SUP>2+</SUP> accumulation in the astroglial culture, but did facilitate impairment in glutathione homeostasis in the same culture. Importantly, treatment with human Cp protein resulted in a significant attenuation against these neurotoxicities induced by Cp ASO. Our results suggest that Cp-mediated neuroprotection occurs via the inhibition of seizure-associated oxidative damage (including impairment in glutathione homeostasis), Fe<SUP>2+</SUP> accumulation, and alterations in ferritin immunoreactivity. Moreover, interactive modulation between neurons and glia was found to be important for Cp upregulation in the attenuation of epileptic damage in both animals and humans.

Gambogic acid induces apoptotic cell death in T98G glioma cells

Thida, M.,Kim, D.W.,Tran, T.T.T.,Pham, M.Q.,Lee, H.,Kim, I.,Lee, J.W. Pergamon Press 2016 Bioorganic & medicinal chemistry letters Vol.26 No.3

Gambogic acid (GA), a natural product with a xanthone structure, has a broad range of anti-proliferative effects on cancer cell lines. We evaluated GA for its cytotoxic effects on T98G glioblastoma cells. GA exhibited potent anti-proliferative activity and induced apoptosis in T98G glioblastoma cells in a dose-dependent manner. Incubation of cells with GA revealed apoptotic features including increased Bax and AIF expression, cytochrome c release, and cleavage of caspase-3, -8, -9, and PARP, while Bcl-2 expression was downregulated. Furthermore, GA induced reactive oxygen species (ROS) generation in T98G cells. Our results indicate that GA increases Bax- and AIF-associated apoptotic signaling in glioblastoma cells.

Effect of different thickness crystalline SiC buffer layers on the ordering of MgB₂ films probed by extended x-ray absorption fine structure

Putri, W. B. K.,Tran, D. H.,Lee, O. Y.,Kang, W. N.,Miyanaga, T.,Yang, D. S.,Kang, B. American Institute of Physics 2014 Journal of Applied Physics Vol.115 No.9

<P>Extended X-ray absorption fine structure (EXAFS) spectroscopy is a powerful method to investigate the local structure of thin films. Here, we have studied EXAFS of MgB2 films grown on SiC buffer layers. Crystalline SiC buffer layers with different thickness of 70, 100, and 130 nm were deposited on the Al2O3 (0001) substrates by using a pulsed laser deposition method, and then MgB2 films were grown on the SiC buffer layer by using a hybrid physical-chemical vapor deposition technique. Transition temperature of MgB2 film decreased with increasing thickness of SiC buffer layer. However, the T-c dropping went no farther than 100 nm-thick-SiC. This uncommon behavior of transition temperature is likely to be created from electron-phonon interaction in MgB2 films, which is believed to be related to the ordering of MgB2 atomic bonds, especially in the ordering of Mg-Mg bonds. Analysis from Mg K-edge EXAFS measurements showed interesting ordering behavior of MgB2 films. It is noticeable that the ordering of Mg-B bonds is found to decrease monotonically with the increase in SiC thickness of the MgB2 films, while the opposite happens with the ordering in Mg-Mg bonds. Based on these results, crystalline SiC buffer layers in MgB2 films seemingly have evident effects on the alteration of the local structure of the MgB2 film. (C) 2014 AIP Publishing LLC.</P>

Wound-healing effect of ginsenoside Rd from leaves of Panax ginseng via cyclic AMP-dependent protein kinase pathway

Kim, W.K.,Song, S.Y.,Oh, W.K.,Kaewsuwan, S.,Tran, T.L.,Kim, W.S.,Sung, J.H. North-Holland ; Elsevier Science Ltd 2013 european journal of pharmacology Vol.702 No.1

Panax ginseng is considered as one of the most valuable medicinal herbs in traditional medicine, and ginsenoside Rd is one of the main active ingredients in P. ginseng leaf. Although there is significant number of evidences implicated on the beneficial effects of the ginsenosides with diverse associated mechanisms, reports on the skin regeneration by the ginsenoside Rd are not sufficient. Therefore, we examined the mitogenic and protective effects of the ginsenoside Rd in the keratinocyte progenitor cells (KPCs) and human dermal fibroblasts (HDFs). Furthermore, the signaling pathways involved in the activation of KPCs and HDFs were investigated, and wound-healing effect is evaluated in vivo through animal wound models. We found that the ginsenoside Rd significantly increased the proliferation and migration level of KPCs and HDFs in a dose-dependent manner. Additionally, the cell survival was significantly increased in H<SUB>2</SUB>O<SUB>2</SUB> treated KPCs. Moreover, the ginsenoside Rd effectively induced collagen type 1 and down-regulated matrix metalloprotinase-1 (MMP-1) in a dose-dependent manner. All of these beneficial effects are associated with an induction of intracellular cAMP levels and phosphorylated cAMP response element-binding protein expression in nucleus, which both attenuated by adenine 9-β-d-arabinofuranoside, an adenylate cyclase inhibitor. Application of the ginsenoside Rd to an excision wound in mice showed an effective healing process. As skin regeneration is mainly associated with the activation of HDFs and KPCs, P. ginseng leaf, an alternative source of the ginsenoside Rd, can be used as a natural source for skin regeneration.

Magnetic and Magnetocaloric Properties of Zn1−x Co x Fe2O4 Nanoparticles

Phan, T. L.,Tran, N.,Kim, D. H.,Dang, N. T.,Manh, D. H.,Bach, T. N.,Liu, C. L.,Lee, B. W. Springer Science + Business Media 2017 Journal of electronic materials Vol.46 No.7

<P>We have prepared Zn1-x Co (x) Fe2O4 nanoparticles (NPs) by using a hydrothermal method, and then studied their structural and magnetic properties. The analyses of x-ray diffraction (XRD) patterns and Raman scattering spectra reveal that the samples crystallized mainly in a cubic-spinel structure with the lattice parameter a ae 8.4 . Averaged crystallite sizes determined from the XRD linewidth are about 16-22 nm, close to the particle sizes of 19-28 nm determined from scanning electron microscopy images. Magnetization measurements versus temperature, M(T), in the field H = 100 Oe indicate that the ferromagnetic-paramagnetic (FM-PM) phase transition temperature (T (C)) of Zn1-x Co (x) Fe2O4 NPs increases from 606 K for x = 0 to similar to 823 K for x = 1. The features of the M(T) curves also indicate magnetic inhomogeneity in the samples, and their magnetic property is unstable versus temperature. This is ascribed to the changes in the structural characterization and/or concentration of magnetic ions situated at the A and B sites in the spinel lattice. At room temperature, we found that both the saturation magnetization (M (s)) and coercivity (H (c)) increase with increasing Co content, with M (s) = 59-70 emu/g and H (c) = 100-1100 Oe. These results reflect that the Co doping into ZnFe2O4 NPs greatly improves their magnetic property, making them more useful for practical applications. Additionally, we also assess magnetic interactions and the magnetocaloric effect in the samples based on analyzing initial magnetization data, M(H), recorded at temperatures around T (C).</P>