Application of polyaniline nanowires electrodeposited on the FTO glass substrate as a counter electrode for low-cost dye-sensitized solar cells

Duong, T.T.,Tuan, T.Q.,Dung, D.V.A.,Van Quy, N.,Vu, D.L.,Nam, M.H.,Chien, N.D.,Yoon, S.G.,Le, A.T. Elsevier 2014 CURRENT APPLIED PHYSICS Vol.14 No.12

Polyaniline nanowires (PANI NWs) were deposited onto fluorine-doped tin oxide (FTO) glass substrate using the cyclic voltammetric method with aniline monomer precursor in HCl aqueous solution. The secondary oxidation peak plays an important role in polymerization of aniline monomer and the optimization of catalytic activity of PANI-based counter electrodes was achieved by controlling the number of cycles. The photovoltaic performance of the dye-sensitized solar cells (DSSCs) with PANI NWs counter electrodes (CEs) was optimized at 4th cycles, and then following parameters were obtained: J<SUB>sc</SUB> = 17.2 mA cm<SUP>-2</SUP>, V<SUB>oc</SUB> = 0.71 V, FF = 59.3%, and efficiency (η) = 7.24%. While, J<SUB>sc</SUB> = 14.7 mA cm<SUP>-2</SUP>, V<SUB>oc</SUB> = 0.77 V, FF = 70.6%, and efficiency (η) = 7.98% in cells with Pt CEs. The PANI NWs were attractive as an alternative CEs for the low-cost DSSCs instead of Pt.

Dynamics and diversity of mosquito vectors of Japanese encephalitis virus in Kandal province, Cambodia

Sebastien Boyer,Borin Peng,Senglong Pang,Véronique Chevalier,Veasna Duong,Christopher Gorman,Philippe Dussart,Didier Fontenille,Julien Cappelle 한국응용곤충학회 2020 Journal of Asia-Pacific Entomology Vol.23 No.4

The Japanese encephalitis virus (JEV) is one of the main causes of encephalitis in Asia, including Cambodia. An understanding of the interactions between JEV hosts and vectors (Diptera: Culicidae) remains rare in the context of expanding urbanization. The relative abundance, species diversity and population dynamics of potential JEV vectors were studied between August 2015 and July 2016 on a peri-urban and rural pig farm in Kandal province, Cambodia, where JEV is circulating. Five similar environments in the two farms were selected for mosquito trapping: pig farm, cattle house, river/canals, household/ponds and paddy fields. The main objective was to describe the distribution and the dynamics of the main JEV vector mosquito species. In total, 83,013 mosquitoes from 20 species were caught in rural and peri-urban areas, and 82.3% of the mosquitoes were potential JEV vector species. In peri-urban areas, Culex (Cx.) gelidus was the most abundant species, followed by Cx. vishnui subgroup and Cx. tritaeniorhynchus. In rural areas, the same species were dominant: Cx. vishnui subgroup, Cx. gelidus and Cx. tritaeniorhynchus. The vast majority of mosquitoes (95.9%) were collected in close proximity to pigs and cattle. In conclusion, JEV vectors were present at all study sites and throughout all months of the year, supporting a continuous circulation of JEV in Cambodia.

Numerical investigations of solidification around a circular cylinder under forced convection

Truong V. Vu,Anh V. Truong,Ngoc T. B. Hoang,Duong K. Tran 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.11

We present numerical investigations of solidification around a cooled circular cylinder in the presence of forced convection. The numerical method is based on the front-tracking/finite difference and interpolation techniques. The solidification interface is represented by connected elements that move on a fixed, rectangular grid. The no-slip and Dirichlet temperature boundary conditions are imposed by the linear interpolation. The interpolation method was first validated through comparisons of the present results with some other numerical results for flow in an annulus, flow in an enclose with a conduction solid body and flow over a heated cylinder. We then used the method to investigate the solidification process around a cold cylinder by varying various parameters such as the Reynolds number Re, the Prandtl number Pr, the Stefan number, the thermal conductivity ratio k sl , the non-dimensional temperature of the introduced liquid q 0 , and the solid-to-liquid density ratio r sl . Numerical results indicate that an increase in any of Re, Pr and q 0 results in a decrease in the area of the solidification region around the cylinder. In contrast, increasing k sl increases the region of the solid phase. Investigation on St and r slreveals that the solidification rate increases with an increase in St or a decrease in r sl . However, St and r sl have a minor effect on the final product of the solidification process.

Precoder Design for Signal Superposition in MIMO-NOMA Multicell Networks

Nguyen, V.,Tuan, H. D.,Duong, T. Q.,Poor, H. V.,Shin, O. IEEE INSTITUTE OF ELECTRICAL AND ELECTRONICS 2017 IEEE journal on selected areas in communications Vol.35 No.12

An efficient procedure for lightweight optimal design of composite laminated beams

V. Ho-Huu,T. Vo-Duy,D. Duong-Gia,T. Nguyen-Thoi 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.27 No.3

A simple and efficient numerical optimization approach for the lightweight optimal design of composite laminated beams is presented in this paper. The proposed procedure is a combination between the finite element method (FEM) and a global optimization algorithm developed recently, namely Jaya. In the present procedure, the advantages of FEM and Jaya are exploited, where FEM is used to analyze the behavior of beam, and Jaya is modified and applied to solve formed optimization problems. In the optimization problems, the objective aims to minimize the overall weight of beam; and fiber volume fractions, thicknesses and fiber orientation angles of layers are selected as design variables. The constraints include the restriction on the first fundamental frequency and the boundaries of design variables. Several numerical examples with different design scenarios are executed. The influence of the design variable types and the boundary conditions of beam on the optimal results is investigated. Moreover, the performance of Jaya is compared with that of the well-known methods, viz. differential evolution (DE), genetic algorithm (GA), and particle swarm optimization (PSO). The obtained results reveal that the proposed approach is efficient and provides better solutions than those acquired by the compared methods.

Degradation-regulated architecture of injectable smart hydrogels enhances humoral immune response and potentiates antitumor activity in human lung carcinoma

Duong, Huu Thuy Trang,Thambi, Thavasyappan,Yin, Yue,Kim, Seong Han,Nguyen, Thanh Loc,Phan, V.H. Giang,Kim, Jaeyun,Jeong, Ji Hoon,Lee, Doo Sung Elsevier 2020 Biomaterials Vol.230 No.-

<P><B>Abstract</B></P> <P>Cancer vaccines that elicit a robust and durable antitumor response show great promise in cancer immunotherapy. Nevertheless, low immunogenicity and weak immune response limit the application of cancer vaccines. To experience next generation cancer vaccines that elicit robust, durable, and anti-tumor T cell response, herein we design injectable smart hydrogels (ISHs) that self-assemble into a cellular microenvironment-like microporous network using a simple hypodermic needle injection, to localize the immune cells and program host cells. ISHs, composed of levodopa- and poly(ε-caprolactone-<I>co</I>-lactide)ester-functionalized hyaluronic acid (HA-PCLA), are loaded with immunomodulatory factor (OVA expressing plasmid, pOVA)-bearing nano-sized polyplexes and granulocyte-macrophage colony-stimulating factor (GM-CSF) as dendritic cell (DC) enhancement factor. Subcutaneous administration of ISHs effectively localized immune cells, and controlled the delivery of immunomodulatory factors to recruit immune cells. The microporous network allowed the recruitment of a substantial number of DCs, which was 6-fold higher than conventional PCLA counterpart. The locally released nano-sized polyplexes effectively internalized to DCs, resulting in the presentation of tumor-specific OVA epitope, and subsequent activation of CD4<SUP>+</SUP> T cells and generation of OVA-specific serum antibody. By the controlled release of nano-sized polyplexes and GM-CSF through a single subcutaneous injection, the ISHs effectively eliminated B16/OVA melanoma tumors in mice. These ISHs can be administered using a minimal invasive technique that could bypass the need for extracorporeal training of cells <I>ex vivo</I>, and provide sustained release of cancer vaccines for immunomodulation. These important findings suggest that ISHs can serve as powerful biomaterials for cancer immunotherapy.</P>

Smart vaccine delivery based on microneedle arrays decorated with ultra-pH-responsive copolymers for cancer immunotherapy

Duong, Huu Thuy Trang,Yin, Yue,Thambi, Thavasyappan,Nguyen, Thanh Loc,Giang Phan, V.H.,Lee, Min Sang,Lee, Jung Eun,Kim, Jaeyun,Jeong, Ji Hoon,Lee, Doo Sung Elsevier 2018 Biomaterials Vol.185 No.-

<P><B>Abstract</B></P> <P>Despite the tremendous potential of DNA-based cancer vaccines, their efficacious delivery to antigen presenting cells to stimulate both humoral and cellular response remains a major challenge. Although electroporation-based transfection has improved performance, an optimal strategy for safe and pain-free vaccination technique remains elusive. Herein, we report a smart DNA vaccine delivery system in which nanoengineered DNA vaccine was laden on microneedles (MNs) assembled with layer-by-layer coating of ultra-pH-responsive OSM-(PEG-PAEU) and immunostimulatory adjuvant poly(I:C), a synthetic double stranded RNA. Transcutaneous application of MN patches onto the mice skin perforate the stratum corneum with minimal cell damage; subsequent disassembly at the immune-cell-rich epidermis/dermis allows the release of adjuvants and DNA vaccines, owing to the ultra-sharp pH-responsive nature of OSM-(PEG-PAEU). The released adjuvant and DNA vaccine can enhance dendritic cell maturation and induce type I interferons, and thereby produce antigen-specific antibody that can achieve the antibody-dependent cell-mediated cytotoxicity (ADCC) and CD8<SUP>+</SUP> T cell to kill cancer cells. Strikingly, transcutaneous application of smart vaccine formulation in mice elicited 3-fold greater frequencies of Anti-OVA IgG1 serum antibody and 3-fold excess of cytotoxic CD8<SUP>+</SUP> T cell than soluble DNA vaccine formulation. As a consequence, the formulation rejected the murine B16/OVA melanoma tumors in C57BL/6 mice through the synergistic activation of antigen-specific ADCC and cytotoxic CD8<SUP>+</SUP> T cells. The maneuvered use of vaccine and adjuvant poly(I:C) in MNs induces humoral and cellular immunity, which provides a promising vaccine technology that shows improved efficacy, compliance, and safety.</P>

Microneedle arrays coated with charge reversal pH-sensitive copolymers improve antigen presenting cells-homing DNA vaccine delivery and immune responses

Duong, Huu Thuy Trang,Kim, Nak Won,Thambi, Thavasyappan,Giang Phan, V.H.,Lee, Min Sang,Yin, Yue,Jeong, Ji Hoon,Lee, Doo Sung Elsevier 2018 Journal of controlled release Vol.269 No.-

<P><B>Abstract</B></P> <P>Successful delivery of a DNA vaccine to antigen-presenting cells and their subsequent stimulation of CD4<SUP>+</SUP> and CD8<SUP>+</SUP> T cell immunity remains an inefficient process. In general, the delivery of prophylactic vaccines is mainly mired by low transfection efficacy, poor immunogenicity, and safety issues from the materials employed. Currently, several strategies have been exploited to improve immunogenicity, but an effective strategy for safe and pain-free delivery of DNA vaccines is complicated. Herein, we report the rapid delivery of polyplex-based DNA vaccines using microneedle arrays coated with a polyelectrolyte multilayer assembly of charge reversal pH-responsive copolymer and heparin. The charge reversal pH-responsive copolymer, composed of oligo(sulfamethazine)-<I>b</I>-poly(ethylene glycol)-<I>b</I>-poly(amino urethane) (OSM-<I>b</I>-PEG-<I>b</I>-PAEU), was used as a triggering layer in the polyelectrolyte multilayer assembly on microneedles. Charge reversal characteristics of this copolymer, that is, the OSM-<I>b</I>-PEG-<I>b</I>-PAEU copolymer exhibit, positive charge at low pH (pH4.03) and becoming negative charge when exposed to physiological pH conditions (pH7.4), allowing the facile assembly and disassembly of polyelectrolyte multilayers. The electrostatic repulsion between heparin and OSM-<I>b</I>-PEG-<I>b</I>-PAEU charge reversal copolymer triggered the release of DNA vaccines. DNA vaccines laden on microneedles are effectively transfected into RAW 264.7 macrophage cells <I>in vitro</I>. Vaccination of BALB/c mice by DNA vaccine-loaded microneedle arrays coated with a polyelectrolyte multilayer generated antigen-specific robust immune responses. These findings provide potential strategy of charge reversal pH-responsive copolymers coated microneedles for DNA vaccine delivery.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Magneto-transport and thermoelectric properties of epitaxial FeSb₂ thin film on MgO substrate (4 pages)

Duong, A.T.,Rhim, S.H.,Shin, Y.,Nguyen, V.Q.,Cho, S. American Institute of Physics 2015 Applied Physics Letters Vol.106 No.3

Exergy assessment of adsorption refrigeration machine

N.V. Cao,X. Q. Duong,Jae Dong Chung 대한설비공학회 2017 대한설비공학회 학술발표대회논문집 Vol.2017 No.11