Slide Session : OS-ALG-04 ; Allergy : Association of Autophagy Related Gene Polymorphisms with Neutrophilic Asthma Phenotype in Korean Adult Asthmatics

( Le Duy Pham ),( Seung Hyun Kim ),( Purevsuren Losol ),( Eun Mi Yang ),( Yoo Seob Shin ),( Young Min Ye ),( Hae Sim Park ) 대한내과학회 2014 대한내과학회 추계학술대회 Vol.2014 No.1

Background: Role of autophagy in neutrophil function and the association of autophagy and autophagy related gene (ATG) polymorphisms with asthma susceptibility were suggested. In this study, we investigated the association of ATG5 and ATG7 polymorphisms with asthma risk, severity and neutrophilic phenotype of asthma. Methods: We recruited 408 asthma patients and 201 healthy controls (NC). Sputum neutrophil counts were determined by H&E staining. Serum IL-8 levels were measured by ELISA. ATG5 gene polymorphisms (-769T>C, -335G>A and 8830C>T) and ATG7 gene polymorphisms (-100A>G and 25108G>C) were genotyped. The functional activities of ATG5 -769T>C and -335G>A variants were investigated by luciferase reporter assays. Results: No associations of ATG5 and ATG7 gene polymorphisms with asthma susceptibility and severity were found. ATG5 -769T>C and -335G>A were in complete linkage disequilibrium. In the asthma group, GA/AA genotypes at ATG5 -335G>A were associated with higher neutrophil counts in sputum (P<0.05); CC/TT genotype at ATG5 8830C>T associated with lower % FEV1 predicted value (P<0.05). DNA fragments containing ATG5 -769T and -335G alleles had higher promoter activities compared to those with -769C and -335A in both human airway epithelial cells (A549, P<0.01) and human mast cell (HMC-1, P<0.001). GG and CC genotype at ATG7 -100A>G and 25108G>C were significantly associated with high serum levels of IL-8 (P<0.05 for both variants). Conclusions: Polymorphisms of ATG5 and ATG7 genes could contribute to neutrophilic phenotype in the pathogenesis of adult asthma.

REVIEWS : What we know about nonsteroidal anti-inflammatory drug hypersensitivity

( Duy Le Pham ),( Ji Hye Kim ),( Tu Hoang Kim Trinh ),( Hae Sim Park ) 대한내과학회 2016 The Korean Journal of Internal Medicine Vol.31 No.3

Nonsteroidal anti-inf lammatory drugs (NSAIDs) are widely prescribed for the treatment of inflammatory diseases, but their use is frequently related to hypersensitivity reactions. This review outlines our current knowledge of NSAID hypersensitivity (NHS) with regard to its pathogenic, molecular, and genetic mechanisms, as well as diagnosis and treatment. The presentation of NHS varies from a local (skin and/or airways) reaction to systemic reactions, including anaphylaxis. At the molecular level, NHS reactions can be classified as cross-reactive (mediated by cyclooxygenase inhibition) or selective (specific activation of immunoglobulin E antibodies or T cells). Genetic polymorphisms and epigenetic factors have been shown to be closely associated with NHS, and may be useful as predictive markers. To diagnose NHS, inhalation or oral challenge tests are applied, with the exclusion of any cross-reactive NSAIDs. For patients diagnosed with NHS, absolute avoidance of NSAIDs/aspirin is essential, and pharmacological treatment, including biologics, is often used to control their respiratory and cutaneous symptoms. Finally, desensitization is recommended only for selected patients with NHS. However, further research is required to develop new diagnostic methods and more effective treatments against NHS.

Epithelial folliculin is involved in airway inflammation in workers exposed to toluene diisocyanate

pham le duy,Tu HK Trinh,반가영,김승현,박해심 생화학분자생물학회 2017 Experimental and molecular medicine Vol.49 No.-

Toluene diisocyanate (TDI) exposure can directly activate and damage airway epithelium. Folliculin (FLCN) is a protein expressed by human airway epithelial cells (HAECs) to maintain airway epithelial integrity and survival. This study investigated the involvement of FLCN in the pathogenesis of TDI-induced occupational asthma (OA). Enzyme-linked immunosorbent assay was used to measure serum levels of FLCN in TDI-exposed subjects (93 TDI-OA patients and 119 asymptomatic exposed controls (AEC)), 200 non-occupational asthma (NOA) patients and 71 unexposed healthy normal controls (NCs). Significantly more subjects in the TDI-OA and AEC groups had high serum levels of FLCN compared to those in the NOA group (P=0.002 and P=0.001, respectively), all of which were higher than the NC group (all Po0.001). The serum level of FLCN was positively correlated with TDI exposure duration (r=0.251, P=0.027), but was negatively correlated with asthma duration of TDI-OA patients (r=− 0.329, P=0.029). TDI-exposed subjects with high FLCN levels had higher serum levels of total IgE than those with lower levels. The effects of TDI exposure on FLCN production was investigated by treating HAECs (A549 cells) with TDIhuman serum albumin conjugate, which showed increased expression and release of FLCN and interleukin-8 from HAECs. Coculture with peripheral blood neutrophils also induced FLCN expression and release from HAECs. In conclusion, TDI exposure and TDI-induced neutrophil recruitment into the airways can activate and stimulate HAECs to produce FLCN, which could be involved in airway inflammation in workers exposed to TDI.

Association of autophagy related gene polymorphisms with neutrophilic airway inflammation in adult asthma

( Duy Le Pham ),( Seung Hyun Kim ),( Purevsuren Losol ),( Eun Mi Yang ),( Yoo Seob Shin ),( Young Min Ye ),( Hae Sim Park ) 대한내과학회 2016 The Korean Journal of Internal Medicine Vol.31 No.2

Background/Aims: Role of autophagy in neutrophil function and the association of autophagy and autophagy related (ATG) gene polymorphisms with asthma susceptibility were suggested. In this study, we investigated the genetic association of ATG5 and ATG7 polymorphisms with asthma risk, severity and neutrophilic airway inflammation. Methods: We recruited 408 asthma patients and 201 healthy controls. Sputum neutrophil counts were determined by H&E staining. Serum interleukin 8 (IL-8) levels were measured by enzyme-linked immunosorbent assay (ELISA). Genetic polymorphisms of ATG5 (-769T>C, -335G>A, and 8830C>T) and ATG7 (-100A>G and 25108G>C) were genotyped. The functional activities of ATG5 -769T>C and -335G>A variants were investigated by luciferase reporter assays. Results: No associations of ATG5 and ATG7 polymorphisms with asthma susceptibility and severity were found. ATG5 -769T>C and -335G>A were in complete linkage disequilibrium. In the asthma group, GA/AA genotypes at ATG5 -335G>A were associated with higher neutrophil counts in sputum (p < 0.05); CC/TT genotype at ATG5 8830C>T associated with lower FEV1% predicted value (p < 0.05). DNA fragments containing ATG5 -769T and -335G alleles had higher promoter activities compared to those with -769C and -335A in both human airway epithelial cells (A549, p < 0.01) and human mast cell (HMC-1, p < 0.001). GG and CC genotype at ATG7 -100A>G and 25108G>C were significantly associated with high serum levels of IL-8 (p < 0.05 for both variants). Conclusions: Genetic polymorphisms of ATG5 and ATG7 could contribute to neutrophilic airway inflammation in the pathogenesis of adult asthma.

Carbon Nanotube-Bridged Graphene 3D Building Blocks for Ultrafast Compact Supercapacitors

Pham, Duy Tho,Lee, Tae Hoon,Luong, Dinh Hoa,Yao, Fei,Ghosh, Arunabha,Le, Viet Thong,Kim, Tae Hyung,Li, Bing,Chang, Jian,Lee, Young Hee American Chemical Society 2015 ACS NANO Vol.9 No.2

<P>The main obstacles to achieving high electrochemical energy density while retaining high power density are the trade-offs of energy <I>versus</I> power and gravimetric <I>versus</I> volumetric density. Optimizing structural parameters is the key to circumvent these trade-offs. We report here the synthesis of carbon nanotube (CNT)-bridged graphene 3D building blocks <I>via</I> the Coulombic interaction between positively charged CNTs grafted by cationic surfactants and negatively charged graphene oxide sheets, followed by KOH activation. The CNTs were intercalated into the nanoporous graphene layers to build pillared 3D structures, which enhance accessible surface area and allow fast ion diffusion. The resulting graphene/CNT films are free-standing and flexible with a high electrical conductivity of 39 400 S m<SUP>–1</SUP> and a reasonable mass density of 1.06 g cm<SUP>–3</SUP>. The supercapacitors fabricated using these films exhibit an outstanding electrochemical performance in an ionic liquid electrolyte with a maximum energy density of 117.2 Wh L<SUP>–1</SUP> or 110.6 Wh kg<SUP>–1</SUP> at a maximum power density of 424 kW L<SUP>–1</SUP> or 400 kW kg<SUP>–1</SUP>, which is based on thickness or mass of total active material.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2015/ancac3.2015.9.issue-2/nn507079x/production/images/medium/nn-2014-07079x_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn507079x'>ACS Electronic Supporting Info</A></P>

Coaxial Fiber Supercapacitor Using All-Carbon Material Electrodes

Le, Viet Thong,Kim, Heetae,Ghosh, Arunabha,Kim, Jaesu,Chang, Jian,Vu, Quoc An,Pham, Duy Tho,Lee, Ju-Hyuck,Kim, Sang-Woo,Lee, Young Hee American Chemical Society 2013 ACS NANO Vol.7 No.7

<P>We report a coaxial fiber supercapacitor, which consists of carbon microfiber bundles coated with multiwalled carbon nanotubes as a core electrode and carbon nanofiber paper as an outer electrode. The ratio of electrode volumes was determined by a half-cell test of each electrode. The capacitance reached 6.3 mF cm<SUP>–1</SUP> (86.8 mF cm<SUP>–2</SUP>) at a core electrode diameter of 230 μm and the measured energy density was 0.7 μWh cm<SUP>–1</SUP> (9.8 μWh cm<SUP>–2</SUP>) at a power density of 13.7 μW cm<SUP>–1</SUP> (189.4 μW cm<SUP>–2</SUP>), which were much higher than the previous reports. The change in the cyclic voltammetry characteristics was negligible at 180° bending, with excellent cycling performance. The high capacitance, high energy density, and power density of the coaxial fiber supercapacitor are attributed to not only high effective surface area due to its coaxial structure and bundle of the core electrode, but also all-carbon materials electrodes which have high conductivity. Our coaxial fiber supercapacitor can promote the development of textile electronics in near future.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2013/ancac3.2013.7.issue-7/nn4016345/production/images/medium/nn-2013-016345_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn4016345'>ACS Electronic Supporting Info</A></P>

What Influences Decision on Seasoned Equity Offerings of Listed Vietnamese Companies?

LE, Long Hau,NGUYEN, Thi Binh Nhi,PHAM, Xuan Quynh,VUONG, Quoc Duy,LE, Tan Nghiem Korea Distribution Science Association 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.5

This paper investigates the determinants on decision to conduct seasoned equity offerings (SEOs) of listed companies on the Ho Chi Minh Stock Exchange in Vietnam. Seasoned equity offerings (SEOs) are defined as the issue of more stocks by a firm to raise more capital after a primary issue. Using panel data collected from audited financial statements of 99 listed companies on the Ho Chi Minh Stock Exchange during 2014-2018, the study employs a logit regression model by fixed effects method to examine factors that affect the decision to implement seasoned equity offerings of those companies. The findings of this study show that profit, revenue growth and company's size have a positively significant impact on the decision, while dividend pay-out ratio negatively significantly influences the equity issuing decision. Furthermore, these results are robust after controlling for the forms of equity offerings, i.e. bonus stocks, stock dividends and rights to buy shares. These findings are consistent with economic theories such as agency theory, pecking order theory, and growth opportunity theory, and also could be explained by the real situations of the Vietnamese stock exchange. This study has important implications for corporate managers, policy makers and investors.

Line Impedance Estimation Based Adaptive Droop Control Method for Parallel Inverters

Le, Phuong Minh,Pham, Xuan Hoa Thi,Nguyen, Huy Minh,Hoang, Duc Duy Vo,Nguyen, Tuyen Dinh,Vo, Dieu Ngoc The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.1

This paper presents a new load sharing control for use between paralleled three-phase inverters in an islanded microgrid based on the online line impedance estimation by the use of a Kalman filter. In this study, the mismatch of power sharing when the line impedance changes due to temperature, frequency, significant differences in line parameters and the requirements of the Plug-and-Play mode for inverters connected to a microgrid has been solved. In addition, this paper also presents a new droop control method working with the line impedance that is different from the traditional droop algorithm when the line impedance is assumed to be pure resistance or pure inductance. In this paper, the line impedance estimation for parallel inverters uses the minimum square method combined with a Kalman filter. In addition, the secondary control loops are designed to restore the voltage amplitude and frequency of a microgrid by using a combined nominal value SOGI-PLL with a generalized integral block and phase lock loop to monitor the exact voltage magnitude and frequency phase at the PCC. A control model has been simulated in Matlab/Simulink with three voltage source inverters connected in parallel for different ratios of power sharing. The simulation results demonstrate the accuracy of the proposed control method.

SCCS: Spatiotemporal clustering and compressing schemes for efficient data collection applications in WSNs

Pham, Ngoc Duy,Le, Trong Duc,Park, Kwangjin,Choo, Hyunseung John Wiley Sons, Ltd. 2010 International Journal of Communication Systems Vol.23 No.11

<P><B>Abstract</B></P><P>The development of large‐scale wireless sensor networks engenders many challenging problems. Examples of such problems include how to dynamically organize the sensor nodes into clusters and how to compress and route the sensing information to a remote base station. Sensed data in sensor systems reflect the spatial and temporal correlations of physical attributes existing intrinsically in the environment. Noteworthy efficient clustering schemes and data compressing techniques proposed recently leverage the spatiotemporal correlation. These include the framework of Liu <I>et al.</I> and schemes introduced by Gedik <I>et al.</I> However, the previous clustering schemes are based on an impractical assumption of a single‐hop network architecture and their cluster construction communication cost is relatively expensive. On the other hand, the computational overhead of recent compressing techniques (e.g. the work of Liu <I>et al.</I> and Douglas <I>et al.</I>) is quite significant; therefore, it is hard for sensor nodes with limited processing capability to perform these techniques. With such motivation, we propose a novel and one‐round distributed clustering scheme based on spatial correlation between sensor nodes, and propose a novel light‐weight compressing algorithm to effectively save the energy at each transmission from sensors to the base station based on temporal correlation of the sensed data. Besides, the aim of the proposed clustering scheme is not only to group the nodes with the highest similarity in observations into the same cluster, but also to construct and maintain a dynamic backbone for efficient data collection in the networks (with the consideration of sink mobility). Computer simulation shows that the proposed schemes significantly reduce the overall number of communications in the cluster construction phase and the energy consumed in each transmission, while maintaining a low variance between the readings of sensor nodes in the same clusters and high reliability of the compressed data. Copyright © 2010 John Wiley & Sons, Ltd.</P>

Controlling a crystalline seed layer for mirocrystalline silicon oxide window layer in rear emitter silicon heterojunction cells

Pham, Duy Phong,Kim, Sangho,Lee, Sunhwa,Le, Anh Huy Tuan,Cho, Eun-Chel,Park, Jinjoo,Yi, Junsin Elsevier 2019 Infrared physics & technology Vol.102 No.-

<P><B>Abstract</B></P> <P>Remarkable progress has been made in the improvement of rear-emitter silicon heterojunction (RE-SHJ) solar cells with the use of very thin n-type front contact layers. However, further reducing the thickness of the front window layers while maintaining high conductivity for mitigating the parasitic absorption and carrier collection loss has proven challenging. In this study, we implement controlling a seed layer for achieving ultra-thin, high crystalline and conductivity of n-type hydrogenated microcrystalline silicon oxide (n-µc-SiO<SUB>x</SUB>:H) front window layer in RE-SHJ solar cells. By using a seed layer, the crystallinity confirmed by Raman and TEM measurements, and the conductivity of the n-µc-SiO<SUB>x</SUB>:H front layers are significantly enhanced compared with that without using the seed layer. This leads to a remarkable increase in the open-circuit voltage (<I>V</I> <SUB>oc</SUB>) by 6 mV and fill factor (<I>FF</I>) by 4.11% while maintaining a high short-circuit current density (<I>J</I> <SUB>sc</SUB>) in range of 38 mA/cm<SUP>2</SUP>. A high cell performance of 21.1% is obtained with the use of an optimised seed layer.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Effect of deposition power densities on seed-growth via TEM measurement was discussed. </LI> <LI> High crystallinity and conductivity of ultra-thin n-µc-SiOx:H front layer for RE-SHJ solar cells. </LI> <LI> V<SUB>oc</SUB> enhancement by 6 mV and fill factor by 4.11% due to optimization of seed layer. </LI> </UL> </P>