Battery-free smart-sensor system for real-time indoor air quality monitoring

Tran, Thang Viet,Dang, Nam Trung,Chung, Wan-Young Elsevier 2017 Sensors and actuators. B Chemical Vol.248 No.-

<P><B>Abstract</B></P> <P>Indoor air pollution is one of the serious issues that affect public health nowadays. Therefore, indoor air quality needs to be monitored by a real-time system for early air pollution warning. Until now, most wireless sensors used for air quality monitoring have required power supply from a battery for sensor operation and wireless data communication. This battery, which is attached to a sensing module, makes the wireless sensing module larger and requires regular replacement efforts and high costs. The present study proposes a novel battery-free sensor module to measure the concentration of volatile organic compounds, ambient temperature, relative humidity, and atmospheric pressure for monitoring air quality in indoor environment. The proposed system comprises a smart-sensor tag, and a radio frequency (RF) energy harvester. The sensing circuit, designed using ultra-low power sensors and a microcontroller unit (MCU), consumes low average power of only 0.5mW. The MCU collects data from the sensors and writes the sensing data to the memory in the form of an Electronic Product Code (EPC) Class 1 Generation 1 compliant identification (ID) of the tag. The RF energy harvester with a highly efficient buck–boost converter and a 50-mF supercapacitor for real-time saving of the collected power can sufficiently collect the available RF energy from the reader within a maximum distance of ∼250cm from the reader to supply power for sensing and wireless communication operation of the smart-sensor tag. Therefore, the proposed smart-sensor module can be a battery-free sensor device for monitoring environment parameters in indoor condition. Experiments are conducted to validate and support the developed system for real-time air quality monitoring and warning.</P> <P><B>Highlights</B></P> <P> <UL> <LI> This paper proposes a novel battery-free sensor module to monitor indoor air quality. </LI> <LI> The proposed smart-sensor module using ultra-low power sensors, a highly efficient radio frequency harvester, and a sequential sensing method does not require any extra battery for operation. </LI> <LI> The proposed study can be a promising solution for real-time air quality monitoring and warning. </LI> </UL> </P>

Outcomes of liver transplantation for hepatocellular carcinoma: Experiences from a Vietnamese center

Khai Viet Ninh,Dang Hai Do,Trung Duc Nguyen,Phuong Ha Tran,Tuan Hoang,Dung Thanh Le,Nghia Quang Nguyen 한국간담췌외과학회 2024 Annals of hepato-biliary-pancreatic surgery Vol.28 No.1

Backgrounds/Aims: Liver transplantation (LT) provides a favorable outcome for patients with hepatocellular carcinoma (HCC) and was launched in Vietnam in 2004. In this study, we evaluated the short-term and long-term outcomes of LT and its risk factors. Methods: This retrospective study analyzed HCC patients who underwent LT at Viet Duc University hospital, Vietnam, from 01/2012–03/2022. The following data were gathered: demographics, virus infection, tumor characteristics, alpha-fetoprotein (AFP) level, Child-Pugh and MELD scores, selection criteria, type of LT, complications, 30-day mortality, and disease-free and overall survival (DFS and OS). Results: Fifty four patients were included, the mean age was 55.39 ± 8.46 years. Nearly 90% had hepatitis B virus-related HCC. The median (interquartile range) AFP level was 16.2 (88.7) ng/mL. The average MELD score was 10.57 ± 5.95; the rate of Child-Pugh A and B were 70.4% and 18.5%, respectively. Nearly 40% of the patients were within Milan criteria, brain-dead donor was 83.3%. Hepatic and portal vein thrombosis occurred in 0% and 1.9%, respectively; hepatic artery thrombosis 1.9%, biliary leakage 5.6%, and postoperative hemorrhage 3.7%. Ninety-day mortality was 5.6%. Five-year DFS and OS were 79.3% and 81.4%, respectively. MELD score and Child- Pugh score were predictive factors for DFS and OS (p < 0.05). In multivariate analysis, Child-Pugh score was the only significant factor (p < 0.05). Conclusions: In Vietnam, LT is an effective therapy for HCC with an acceptable complication rate, mortality rate, and good survival outcomes, and should be further encouraged.

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.

R&D, training and accessibility to finance for innovation: a case of Vietnam, the country in transition

Kim Won Joong,Hoi Tran Viet,Tuan La Ngoc,Trung Nguyen Ngoc 기술경영경제학회 2019 ASIAN JOURNAL OF TECHNOLOGY INNOVATION Vol.27 No.2

Innovation is consulted a very important activity for any firm and organization especially for business units in a transitional country. By using a binary logistic regression with Vietnam Enterprise Surveys data from World Bank project, this research finds that R&D played a vital role in encouraging innovative activities. Moreover, formal training within businesses has very strong and significant effects on all four different measures of innovation. What's more is that if a manager has experience of 5 or 15 in years in comparison with longer years of experience, marginal effects to probability of occurrence for organizational innovation likely come into being higher. Interestingly, higher obstacles for accessing to financial resources do not reduce innovative level but it does get business units have higher propensity to marketing innovation.

Short packet communication in underlay cognitive network assisted by an intelligent reflecting surface

Pham Ngoc Son,Tran Trung Duy,Pham Viet Tuan,Tan-Phuoc Huynh Electronics and Telecommunications Research Instit 2023 ETRI Journal Vol.45 No.1

We propose short packet communication in an underlay cognitive radio network assisted by an intelligent reflecting surface (IRS) composed of multiple reconfigurable reflectors. This scheme, called the IRS protocol, operates in only one time slot (TS) using the IRS. The IRS adjusts its phases to give zero received cumulative phase at the secondary destination, thereby enhancing the end-to-end signal-to-noise ratio. The transmitting power of the secondary source is optimized to simultaneously satisfy the multi-interference constraints, hardware limitations, and performance improvement. Simulation and analysis results of the average block error rates (BLERs) show that the performance can be enhanced by installing more reconfigurable reflectors, increasing the blocklength, lowering the number of required primary receivers, or sending fewer information bits. Moreover, the proposed IRS protocol always outperforms underlay relaying protocols using two TSs for data transmission, and achieves the best average BLER at identical transmission distances between the secondary source and secondary destination. The theoretical analyses are confirmed by Monte Carlo simulations.

The Facile Synthesis of Novel ZnO Nanostructure for Galactose Biosensor Application

La Phan, Phuong Ha,Tran, Quang Trung,Dinh, Duc Anh,Bok, Ko Kang,Hong, Chang-Hee,Cuong, Tran Viet Hindawi Limited 2019 Journal of nanomaterials Vol.2019 No.-

<P>We introduce a novel structure of ZnO nanorods (NRs) grown on ZnO NRs (ZnO NRs/NRs) via a facile, low-cost, and environmentally friendly synthesis for galactose biosensor application. The galactose oxidase enzyme (GalOx) is immobilized on the ZnO NR/NR surface to form the novel electrode structure (GalOx|ZnO NRs/NRs). The GalOx|ZnO NR/NR electrode has a linear detection range of current density from 11.30 <I>μ</I>A/mm<SUP>2</SUP> to 18.16 <I>μ</I>A/mm<SUP>2</SUP> over a galactose concentration range from 40 mM to 230 mM, indicating the increment of electrode sensitivity up to 60.7%. The ZnO NR/NR morphology with a high surface area to volume ratio has a great contribution to the electrochemical performance of galactose biosensor. Our results propose a straightforward approach to fabricate architecturally ZnO-based nanostructure for biosensor application.</P>

Zanthoxylum rhetsa Stem Bark Extract Inhibits LPS-induced COX-2 and iNOS expression in RAW 264.7 Cells via the NF-kB Inactivation

Nguyen Bich Thu,Trinh Nam Trung,Do Thi Ha,Nguyen Minh Khoi,Nguyen Viet Than,Thipthaviphone Soulinho,Nguyen Hai Nam,Tran Thi Phuong,배기환 한국생약학회 2010 Natural Product Sciences Vol.16 No.4

The methanol extract of Zanthoxylum rhetsa (MZRR) were evaluated for its ability to suppress the formation of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in lipopolysaccharide (LPS)-activated RAW 264.7 macrophages. MZRR presented an inhibition of LPS-induced production of nitric oxide (NO) and prostaglandin E2 (PGE2) in RAW 264.7 macrophages. Western blotting and RT-PCR analyses demonstrated that MZRR significantly inhibited the protein and mRNA expressions of iNOS and COX-2 in LPS-activated macrophages in a dose-dependent manner. LPS-induced COX-2, iNOS, and nuclear factor kappa beta (NF-kB) activity were also decreased in the presence of MZRR. The production of tumor necrosis factor-a (TNF-a), the mRNA expression levels of pro-inflammatory cytokines, including TNF-a and IL-1b, were reduced after MZRR administration in a dose dependent-manner. These results suggest that the MZRR extract involved in the inhibition of iNOS and COX-2 via the NF-kB pathway, revealing a partial molecular basis for anti-inflammatory properties of the MZRR extract.

Characterization of Ag-Doped p-Type SnO Thin Films Prepared by DC Magnetron Sputtering

Pham, Hoai Phuong,Thuy, Thanh Giang Le,Tran, Quang Trung,Nguyen, Hoang Hung,My Hoa, Huynh Tran,Thi Thu, Hoang,Cuong, Tran Viet Hindawi Limited 2017 Journal of nanomaterials Vol.2017 No.-

<P>Crystalline structure and optoelectrical properties of silver-doped tin monoxide thin films with different dopant concentrations prepared by DC magnetron sputtering are investigated. The X-ray diffraction patterns reveal that the tetragonal SnO phase exhibits preferred orientations along (101) and (110) planes. Our results indicate that replacing Sn<SUP>2+</SUP> in the SnO lattice with Ag<SUP>+</SUP> ions produces smaller-sized crystallites, which may lead to enhanced carrier scattering at grain boundaries. This causes a deterioration in the carrier mobility, even though the carrier concentration improves by two orders of magnitude due to doping. In addition, the Ag-doped SnO thin films show a p-type semiconductor behavior, with a direct optical gap and decreasing transmittance with increasing Ag dopant concentration.</P>

Applying the IoT platform and green wave theory to control intelligent traffic lights system for urban areas in Vietnam

Phan, Cao Tho,Pham, Duy Duong,Tran, Hoang Vu,Tran, Trung Viet,Huu, Phat Nguyen Korean Society for Internet Information 2019 KSII Transactions on Internet and Information Syst Vol.13 No.1

This paper proposes an intelligent system performing an application with assistance of an Internet of Things (IoT) platform to control a traffic lights system. In our proposed systems, the traffic lights can be remotely controlled through the Internet. Based on IoT platform, the traffic conditions at different intersections of roads are collected and the traffic lights are controlled in a central manner. For the software part, the algorithm is designed based on the green wave theory to maximize the green bandwidth of arterial roads while addressing a challenging issue: the rapid changes of parameters including cycle time, splits, offset, non-fixed vehicles' velocities and traffic flow along arterial roads. The issue typically happens at some areas where the transportation system is not well organized like in Vietnam. For the hardware part, PLC S7-1200 are placed at the intersections for two purposes: to control traffic lights and to collect the parameters and transmit to a host machine at the operation center. For the communication part, the TCP/IP protocol can be done using a Profinet port embedded in the PLC. Some graphical user interface captures are also presented to illustrate the operation of our proposed system.

Screening of Vietnamese Medicinal Plants for Cytotoxic Activity

Nguyen Bich Thu,Trinh Nam Trung,Do Thi Ha,Nguyen Minh Khoi,Tran Viet Hung,Tran Thi Hien,Yim Namhui,배기환 한국생약학회 2010 Natural Product Sciences Vol.16 No.1

Thirty-two methanol extracts of thirty-one Vietnamese medicinal plants were evaluated for the cytotoxic activity against five human cancer cell lines, including A549, MCF-7, HT 1080, Huh-7, and HepG2. Of these, the nine extracts of Acanthopanax trifoliatus (4), Acanthopanax gracilistylus (5), Siegesbeckia orientalis (10), Betula alnoides (11), Passiflora edulis (18), Zanthoxylum simulans (leaf, 23), Adenosma caeruleum (26), Solanum verbascifolium (29), and Alpinia malaccensis (31), exhibited high potent cytotoxic activity showing a certain degree of selectivity against the different cell types, with IC50 values ranging from 2.1 to 3.8 mg/mL.