Fabrication of Planar Waveguide Chip for Splitting or Combining an Infrared Light Beam

Nguyen Thanh Binh,Nguyen Tat Thanh,Duong Thanh Trung,Nguyen Thanh Huong,Le Quoc Minh 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.5

Based on hybrid materials of polymethamethyl acrylat, silica and zirconia (ASZ)/Titania (AST), some planar structures of optical power splitter/combiner type 1×N channels were designed and simulated for making masks by using computer software. Splitter chips were then fabricated by using the thin-film sol-gel technique and their structure was formed by using a direct photo-patterning method with UV light and a mask. A conformation of the waveguide was tested with an Alpha-Step IQ system. The waveguide properties of the splitter were measured with a 1550 nm laser source. The experimental results show that the light was transmitted through the chip with a total output efficiency of around 6% and was separated uniformly at the output channels. Based on hybrid materials of polymethamethyl acrylat, silica and zirconia (ASZ)/Titania (AST), some planar structures of optical power splitter/combiner type 1×N channels were designed and simulated for making masks by using computer software. Splitter chips were then fabricated by using the thin-film sol-gel technique and their structure was formed by using a direct photo-patterning method with UV light and a mask. A conformation of the waveguide was tested with an Alpha-Step IQ system. The waveguide properties of the splitter were measured with a 1550 nm laser source. The experimental results show that the light was transmitted through the chip with a total output efficiency of around 6% and was separated uniformly at the output channels.

Micropropagation from root segments to improve seedling quality in Chinese foxglove crops

Thanh Loan Pham,Van Huy Nguyen,Thi Le Thu Hoang,Thi Tam Tien Ha,Trung Kien Tran,Xuan Duong Vu,Phi Bang Cao,Quang Trung Nguyen 한국식물생명공학회 2020 JOURNAL OF PLANT BIOTECHNOLOGY Vol.47 No.3

This is the first study to establish a complete protocol for micropropagation of Rehmannia glutinosa from root segments. The study involved investigating the effect of plant growth regulators on in vitro shoot regeneration and rooting and identifying substrates supporting survival and growth performance of ex vitro seedlings. A Murashige and Skoog (MS) medium containing 30 g/L sucrose for shoot induction and 0.2 mg/L indole-3-acetic acid (IAA), 1 mg/L 6-benzylaminopurine (BAP), and 1 g/L polyvinylpyrrolidone (PVP) for shoot multiplication resulted in the highest number of shoots per explant and shoot height. Applying a medium containing 0.5 mg/L IAA and 1 g/L PVP yielded optimal rooting of the shoots grown in vitro. Compost enriched with microbial inoculants and perlite enhanced seedling growth better than that with organic biofertilizer-free substrates (soil and sand). We recommend the continuous production of micropropagated R. glutinosa seedlings from root segments under the aforementioned conditions as a possible propagation technique for crops of this species.

An Extension of Theory of Planned Behavior for in-App Advertisements: The Case of Vietnamese Young Mobile Users

Tommi Tapanainen,Trung Kien Dao,Thi Thanh Hai Nguyen,Thi Anh Duong Pham,Danh Nguyen Nguyen 한국데이타베이스학회 2020 Journal of information technology applications & m Vol.27 No.1

In-app advertisement is a fast-growing trend in mobile advertising, where user acceptance of ads is facilitated by the fact that users have voluntarily downloaded the app through which the ad is served. However, research in this ad category is limited. This study applies an extended version of the theory of planned behavior. Analysis results from 412 young mobile users in Vietnam using structural equation modeling showed that while localization and perceived enjoyment affected user intention to watch in-app ads as expected, perceived behavioral control and trust did not. Such results may be due to embedding the ads to applications, confusing users’ behavioral intentions. The results underline the need for more future research in the area. In practical terms, companies should improve localization and entertainment aspects of ads to create more relevant and engaging advertisements.

Pandemics and Economic Complexity: A Cross-Country Analysis

Nguyen Dinh Trung,Duong Kim Thanh,Phung Huong Thi Thu,Ha Mai Quynh 한국국제경제학회 2024 International Economic Journal Vol.38 No.1

This paper is the first attempt to empirically examine the impact of pandemics on economic complexity in a cross-country setting. We employ a unique and recently developed measure of pandemic intensity, which is the World Pandemic Discussion Index. Using panel-corrected standard error regressions on a panel dataset of 90 countries from 1996 to 2019, we find that an increase in pandemic discussion could reduce economic complexity. Further heterogeneity tests show that this detrimental effect of pandemics only occurs in emerging and low-income countries, or in countries with low levels of institutional quality. By using mechanism analysis,wealso find that pandemics reduce economic complexity via deteriorating the quality of human capital. These findings are robust to a comprehensive battery of robustness and sensitivity checks. Overall, our paper could provide valuable implications for policy makers in devising measures to support the economic recovery process post-pandemics.

The impact of hyperandrogenism on the outcomes of ovulation induction using gonadotropin and intrauterine insemination in women with polycystic ovary syndrome

Ho, Vu Ngoc Anh,Pham, Toan Duong,Nguyen, Nam Thanh,Hoang, Hieu Le Trung,Ho, Tuong Manh,Vuong, Lan Ngoc The Korean Society for Reproductive Medicine 2022 Clinical and Experimental Reproductive Medicine Vol.49 No.2

Objective: This study aimed to investigate the impact of hyperandrogenism (HA) on the outcomes of ovulation induction (OI) using gonadotropin and intrauterine insemination (IUI) in patients with polycystic ovary syndrome (PCOS). Methods: This was a retrospective cohort study including 415 patients undergoing OI using gonadotropin and IUI treatment between January 2018 and December 2020 at a single infertility center. Baseline characteristics, clinical and laboratory parameters, and pregnancy outcomes were investigated. Results: Among the study population, there were 105 hyperandrogenic (25.3%) and 310 non-hyperandrogenic patients (74.7%). The live birth rate was lower in the HA group than in the non-HA group, but this difference did not reach statistical significance due to the limited sample size (14.3% vs. 21.0%, relative risk=0.68; 95% CI, 0.41-1.14, p=0.153). No predictive factors for live birth were identified through logistic regression analysis. Conclusion: HA did not negatively affect the outcomes of OI using gonadotropin and IUI cycles in Vietnamese women with PCOS. The result may not be applicable elsewhere due to the large variation in the characteristics of women with PCOS across races and populations.

Dielectric and ferroelectric characteristics of doped BZT-BCT ceramics sintered at low temperature

Dang Anh Tuan,Le Dai Vuongb,Vo Thanh Tung,Ngo Ngoc Tuan,Nguyen Trung Duong 한양대학교 세라믹연구소 2018 Journal of Ceramic Processing Research Vol.19 No.1

The paper presents relaxor properties of lead-free nanostructured ZnO doped BZT-BCT ceramics sintered at lowtemperature. Curie-Weiss, Quadratic, Vogel-Fulcher laws were applied to study dielectric properties. The fitting experimentaldata to the mentioned laws showed the typical diffuseness characteristic of the materials as a result of the substitution of Zn2+ions into BZT-BCT substrate. Also, received ferroelectric loops were well saturated and fairly slim for all samples that assert againdiffuse ferroelectric nature in the investigated ceramics. The characterized values of remnant polarization, Pr, and coercive field,Ec, depended on ZnO nanoparticles concentration. According to that, when varying doping content in the region of 0.00-0.25%wt,Pr improved and reached a maximum value of 6.19 μC/cm2 at 0.15%wt, then decreased monotonously. Meanwhile Eccontinuously intensified in the range of 1.36-2.72 kV/cm. In other words, nanosized ZnO particles made the ceramics harder

Banking Sector Depth and Economic Growth: Empirical Evidence from Vietnam

LE, Thi Thuy Hang,LE, Trung Dao,TRAN, Thi Dien,DUONG, Quynh Nga,DAO, Le Kieu Oanh,DO, Thi Thanh Nhan Korea Distribution Science Association 2021 The Journal of Asian Finance, Economics and Busine Vol.8 No.3

The Vietnamese economy is a developing country that has brought many opportunities and challenges for the banking system. Commercial banks have developed strongly from quality to quantity, which plays a vital role in developing the economy. They play an important role in capital formation, which is essential for the economic development of a country. They provide financial services to the general public and businesses, ensuring economic and social stability and sustainable growth of the economy. Therefore, the relationship between bank depth and economic growth is of importance in research. This paper used a VAR (Vector Autoregressive Models) estimator for time series data models. The data is collected quarterly from the first quarter of the year 2000 to 2020. The study uses the VAR model to examine the causal relationships of economic growth, growth in money supply expansion, private sector capital requirement, and banks' domestic credit. The results indicate a general short-run relationship between banking sector depth and economic growth with a positive connection, but in the long term, the relationship between these variables can be reversed because of other macro factors. The findings show the two-way causal relationship between GDP growth and banking depth factors. This research contributes to policy-making by underlining the banking sector depth determinants when setting regulations and policies to develop the banking sector.

Thinning and drilling laser-assisted hatching in thawed embryo transfer: A randomized controlled trial

Le, Minh Tam,Nguyen, Thi Tam An,Nguyen, Thi Thai Thanh,Nguyen, Van Trung,Le, Dinh Duong,Nguyen, Vu Quoc Huy,Cao, Ngoc Thanh,Aints, Alar,Salumets, Andres The Korean Society for Reproductive Medicine 2018 Clinical and Experimental Reproductive Medicine Vol.45 No.3

Objective: In frozen and thawed embryos, the zona pellucida (ZP) can be damaged due to hardening. Laser-assisted hatching (LAH) of embryos can increase the pregnancy rate. This study compared thinning and drilling of the ZP before frozen embryo transfer (FET). Methods: Patients were randomly allocated into two groups for LAH using thinning or drilling on day 2 after thawing. Twenty-five percent of the ZP circumference and 50% of the ZP thickness was removed in the thinning group, and a hole $40{\mu}m$ in diameter was made in the drilling group. Results: A total of 171 in vitro fertilization/intracytoplasmic sperm injection FET cycles, including 85 cycles with drilling LAH and 86 cycles with thinning LAH, were carried out. The thinning group had a similar ${\beta}$-human chorionic gonadotropin-positive rate (38.4% vs. 29.4%), implantation rate (16.5% vs. 14.4%), clinical pregnancy rate (36.0% vs. 25.9%), miscarriage rate (5.8% vs. 2.4%), ongoing pregnancy rate (30.2% vs. 23.5%), and multiple pregnancy rate (7.0% vs. 10.6%) to the drilling LAH group. There were no significant differences in pregnancy outcomes between subgroups defined based on age (older or younger than 35 years) or ZP thickness (greater or less than $17{\mu}m$) according to the LAH method. Conclusion: The present study demonstrated that partial ZP thinning or drilling resulted in similar outcomes in implantation and pregnancy rates using thawed embryos, irrespective of women's age or ZP thickness.

Impact of long COVID-19 on posttraumatic stress disorder as modified by health literacy: an observational study in Vietnam

Han Thi Vo,Tien Duc Dao,Tuyen Van Duong,Tan Thanh Nguyen,Binh Nhu Do,Tinh Xuan Do,Khue Minh Pham,Vinh Hai Vu,Linh Van Pham,Lien Thi Hong Nguyen,Lan Thi Huong Le,Hoang Cong Nguyen,Nga Hoang Dang,Trung 질병관리청 2024 Osong Public Health and Research Persptectives Vol.15 No.1

Objectives: The incidence of posttraumatic stress disorder (PTSD) has increased, particularly among individuals who have recovered from coronavirus disease 2019 (COVID-19) infection. Health literacy is considered a “social vaccine” that helps people respond effectively to the pandemic. We aimed to investigate the association between long COVID-19 and PTSD, and to examine the modifying role of health literacy in this association.Methods: A cross-sectional study was conducted at 18 hospitals and health centers in Vietnam from December 2021 to October 2022. We recruited 4,463 individuals who had recovered from COVID-19 infection for at least 4 weeks. Participants provided information about their sociodemographics, clinical parameters, health-related behaviors, health literacy (using the 12-item short-form health literacy scale), long COVID-19 symptoms and PTSD (Impact Event Scale-Revised score of 33 or higher). Logistic regression models were used to examine associations and interactions.Results: Out of the study sample, 55.9% had long COVID-19 symptoms, and 49.6% had PTSD. Individuals with long COVID-19 symptoms had a higher likelihood of PTSD (odds ratio [OR], 1.68; 95% confidence interval [CI], 1.63–2.12; p<0.001). Higher health literacy was associated with a lower likelihood of PTSD (OR, 0.98; 95% CI, 0.97–0.99; p=0.001). Compared to those with long COVID-19 symptoms and the lowest health literacy score, those with long COVID-19 symptoms and a 1-point health literacy increment had a 3% lower likelihood of PTSD (OR, 0.97; 95% CI, 0.96–0.99; p=0.001).Conclusion: Health literacy was found to be a protective factor against PTSD and modified the negative impact of long COVID-19 symptoms on PTSD.