Alpha-Glucosidase Inhibitory Activity of Saponins Isolated from Vernonia gratiosa Hance

Cong Pham Van,Anh Hoang Le Tuan,Vinh Le Ba,Han Yoo Kyong,Trung Nguyen Quang,Minh Bui Quang,Duc Ngo Viet,Ngoc Tran Minh,Hien Nguyen Thi Thu,Manh Hoang Duc,Lien Le Thi,Lee Ki Yong 한국미생물·생명공학회 2023 Journal of microbiology and biotechnology Vol.33 No.6

Species belonging to the Vernonia (Asteraceae), the largest genus in the tribe Vernonieae (consisting of about 1,000 species), are widely used in food and medicine. These plants are rich sources of bioactive sesquiterpene lactones and steroid saponins, likely including many as yet undiscovered chemical components. A phytochemical investigation resulted in the separation of three new stigmastane-type steroidal saponins (1 – 3), designated as vernogratiosides A–C, from whole plants of V. gratiosa. Their structures were elucidated based on infrared spectroscopy  (IR), one-dimensional (1D) and two-dimensional nuclear magnetic resonance (2D NMR), high-resolution electrospray ionization mass spectrometry (HR-ESI-MS), and electronic circular dichroism analyses (ECD), as well as chemical reactivity. Molecular docking analysis of representative saponins with αglucosidase inhibitory activity was performed. Additionally, the intended substances were tested for their ability to inhibit α-glucosidase activity in a laboratory setting. The results suggested that stigmastane-type steroidal saponins from V. gratiosa are promising candidate antidiabetic agents.

Perceived Risk of Sharing Other People’s Information on Facebook: The Perspective of Young People in Ho Chi Minh City, Vietnam

Dinh Tien Minh,Tran Ngoc Thuy,Ngo Nguyen Gia Nghi,Nguyen Yen Vy,Nguyen Thi Thanh Lam,Pham Cong Minh KINFORMS 2021 Management Review Vol.16 No.2

In Vietnam, young people are gradually becoming the most accessible objects to social networks. With the development of technology, they usually use online social networks (ONS) as a tool to update information through multimedia content, which may contain other people s information. In different cases, other people s information will be shared and received for different purposes. Therefore, the risk is inevitable and may affect the privacy of individuals whose information is shared, causing turbulence in the community. This study aims to measure impact and find out the factors that influence the willingness of others to share information on social networks in Ho Chi Minh City by examining young people s perceptions that their activities on Facebook may be risky for other people s information. Besides that, the study proposes solutions to avoid possible risks when sharing information with others.

Additive biocomponents from catfish by-products enhance the growth of shrimp Litopenaeus vannamei

Pham Viet Nam,Tran Vy Hich,Nguyen Van Hoa,Khuong V. Dinh,Nguyen Cong Minh,Trang Si Trung 한국수산과학회 2023 Fisheries and Aquatic Sciences Vol.26 No.6

The rapid expansion of shrimp production requires a huge amount of protein sources from soybeans and wild-caught fishmeal; both are becoming a shortage. Meanwhile, catfish production and processing is a giant industry in Vietnam, which produce hundred thousand tonnes of protein- and lipid-rich by-products, annually. Using catfish by-products to gradually replace the traditional protein sources in shrimp aquaculture may bring triple benefits: 1) reducing pressure on wild fish exploitation for fishmeal, 2) reducing the environmental impacts of catfish by-products, and 3) increasing the value and sustainability of aquaculture production. In this study, we used catfish by-products to produce fish protein hydrolysate (FPH) and nano-hydroxyapatite (HA) as additives in feed for Pacific white shrimp (Litopenaeus vannamei). The supplement mixture of FPH and HA was added into the commercial diet (Charoen Pokphand Group [CP], 38% protein, and 6.5% lipid) to reach 38%, 38.5%, 40%, 43%, and 44% of the crude protein content. The survival and growth of shrimps were weekly assessed to day 55. The results showed that the shrimp growth was highest at 43% crude protein content in the feed as indicated by an increase of 124% and 112% in shrimp weight and length, respectively, compared to the commercial reference diet. No negative effects of adding the mixture of FPH and HA on the water quality were observed. Vibrio density was lower than 6.5 × 103 CFU/mL, which is the lowest Vibrio density negatively affecting the shrimp growth and development. These findings indicate that the mixture of FPH and HA are promising additive components in feed for post-larval shrimp L. vannamei diets.

A Study on Characteristics of Power Generation System Using Biogas from the Waste of Pig Farm

Thanh-Cong Huynh,Xuan-Mai Pham,Dinh-Hung Nguyen,Minh-Tien Tran 한국수소및신에너지학회 2010 한국수소 및 신에너지학회논문집 Vol.21 No.5

electric production, a SI gasoline engine is modified to use biogas fuel and was installed in a 20 KVA power generation system. An electronic speed regulation unit is developed to keep the system speed at 1500rpm. Experimental investigations have been carried out to examine the performance characteristics of power generation system (such as: system frequency, phase output voltage,...). In addition, the operating parameters and output emissions (NOx, HC, and CO2) of biogas-fueled engine are preliminary evaluated and analyzed for the change of system load. Results indicated that the researched power generation system shows a high stability of output voltage and frequency with help of speed regulator. Biogas fuel (mainly CH4 and CO2) has an environmental impact and potential as a green alternative fuel for SI engine and they would not require significant modification of existing engine hardware. Output emissions of biogas-fueled engine are found to be relative low. NOx emission increases with the increase of output electric power of the power generation system.

Heat Transfer Performance Optimization of Rectangular Channel with Truncated-root Ribs

Ky-Quang Pham,Van-Minh Le,Cong-Truong Dinh 한국유체기계학회 2022 International journal of fluid machinery and syste Vol.15 No.2

Cooling designs inside the gas turbine blades of aircraft engines are aimed to solve a problem that has existed since the very beginning of the aerospace industry. Since the working environment of turbine blades is extremely harsh when the temperature can rise to 2000K, which is considered a huge challenge for any materials. Therefore, cooling designs such as rib turbulators have always been researched and optimized for better heat transfer enhancement in the cooling mechanism of turbine blades. In this study, a geometric optimization of the rib turbulators inside a rectangular channel was performed with the aim to maximize heat transfer performance. This study investigated the effect of four rib configurations on the heat transfer efficiency of the channel, which include square, truncated-root, convergent truncated-root, and divergent truncated-root rib. Thereby, a module of coupling Python and OpenFOAM was developed to automatically perform the optimization of truncated-root rib design at Reynolds number of 37,000 with design variables are the upstream and downstream height with Powell optimization method. The aim is to figure out the point where the maximum heat transfer performance of the channel is achieved. The study presented in a specific, productive, and accurate way the factors that directly and indirectly affect the heat transfer performance of the channel, thereby giving the optimal results that the channel has the highest heat transfer performance of the presented designs. The results show that the highest heat transfer performance of the optimized design is 12.45% higher than the standard square ribs case.

Aerodynamic drag of axisymmetric models with different boattail angles under subsonic and supersonic flow conditions

The Hung Tran,Cong Truong Dao,Dinh Anh Le,Van Khiem Pham,Van Minh Do,Trang Minh Nguyen 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.12

This study examines the drag trend and flow behavior of axisymmetric models with conical boattails under subsonic and supersonic conditions by using a numerical approach. Mach numbers ranging from 0.1 to 3.0 and boattail angles varying from 0° to 24° are investigated. The numerical results are validated by experimental data under identical flow conditions. The flow behavior around the boattail body, the total drag, and the pressure distribution are analyzed in detail. The drag components acting on the boattail surface are examined to determine the reason for the change in drag due to different boattail angles and Mach number conditions. Results show that the minimum drag is around 14° for subsonic flow, but this value suddenly decreases to around 7° for supersonic flow. Formalization of the expansion and oblique shocks on the boattail is the main cause of changes in the pressure distribution on the surfaces, which in turn affect the drag trend. Moreover, the relationships among boattail angle, flow conditions, and four flow types on the boattail surface are presented in detail.

A fault detection and diagnosis approach for multi-tier application in cloud computing

Khiet Thanh Bui,Len Van Vo,Canh Minh Nguyen,Tran Vu Pham,Hung Cong Tran 한국통신학회 2020 Journal of communications and networks Vol.22 No.5

Ensuring the availability of cloud computing services always concerns both service providers and end users. Therefore, the system always needs precautions for unexpected cases. Accordingly, cloud computing services mustbe capable of identifying faults and behaving appropriatelywhen it is abnormal to ensure the smoothness as well asthe service quality. In this study, we propose a fault detection method for multi-tier web application in cloud computing deployment environment based on the Fuzzy Oneclass support vector machine and Exponentially WeightedMoving Average method. And then, the suspicious metrics are located by using feature selection method whichbased on Random Forest algorithm. To evaluate our approach, a multi-tier application is deployed by a transnational web e-Commerce benchmark by using TPC-W (TPCBenchmark™ W, simulates the activities of a business oriented transaction web server in a controlled internet commerce environment) in private cloud and then it is injectedtypical faults. The effectiveness of the fault detection anddiagnosis are demonstrated in experiment results.

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.

Assessment of Left Ventricular Function and Regional Wall Motion by 256-Slice Dual-Source Coronary CT Angiography: A Comparison With 2D Transthoracic Echocardiography

Le Thi Thuy Lien,Nguyen Khoi Viet,Hoang Van Hoa,Phung Bao Ngoc,Nguyen Ngoc Trang,Vu Thi Kim Thoa,Nguyen Cong Tien,Phan Anh Phuong,Pham Minh Thong,Vu Dang Luu 아시아심장혈관영상의학회 2022 Cardiovascular Imaging Asia Vol.6 No.2

Objective: To compare left ventricular (LV) function, ejection fraction (EF), end-diastolic volume (EDV), end-systolic volume (ESV), and regional wall motion analyzed in 256-slice dualsource coronary CT angiography (DSCT) with 2D transthoracic echocardiography (TTE). Materials and Methods: One hundred twelve patients suspected of coronary artery disease underwent DSCT and 2D-TTE within one week for LVEF, EDV, and ESV. The correlation between DSCT and 2D-TTE measurements was analyzed through linear regression and Bland- Altman analysis. Regional wall motion was visually scored with a 3-point scale (1, normal; 2, hypokinesia; 3, dysphagia, akinesia). Results: Average LVEF at 66.45%±1.27% (range 23%–85%) as determined on DSCT compared with 66.09%±1.01% (range 25%–84%) on 2D-TTE. LVEF exhibited a good correlation between DSCT and 2D-TTE (r=0.715; p<0.001). Good correlations between DSCT and 2D-TTE were demonstrated for LVEDV (r=0.732; p<0.001) and LVESV (r=0.841; p<0.001). Mean differences (±SD) of 1.78±24.10 mL (p<0.05) and 0.77±13.70 mL (p<0.05) were observed between DSCT and 2D-TTE for LVEDV and LVESV, respectively. LVEF was slightly overestimated with DSCT (0.52%±9.59%; p<0.05). Although the LVEF values calculated by DSCT and 2D-TTE were similar, EDV and ESV from DSCT were statistically higher than those from 2D-TTE (p<0.05). Agreement between DSCT and 2D-TTE in regional wall motion was 96.4%, κ=0.840. Conclusion: DSCT can provide comparable results to those using 2D-TTE for LV function (EF, EDV, and ESV) and regional wall motion assessment in a heterogeneous population.