Search

Your search keyword '"Nguyen Duy, Phuong"' showing total 128 results
Start Over Author "Nguyen Duy, Phuong"
128 results on '"Nguyen Duy, Phuong"'

1. MAGICS: Adversarial RL with Minimax Actors Guided by Implicit Critic Stackelberg for Convergent Neural Synthesis of Robot Safety

Author

Wang, Justin, Hu, Haimin, Nguyen, Duy Phuong, and Fisac, Jaime Fernández

Subjects
Computer Science - Robotics, Computer Science - Artificial Intelligence, Computer Science - Machine Learning, Electrical Engineering and Systems Science - Systems and Control
Abstract

While robust optimal control theory provides a rigorous framework to compute robot control policies that are provably safe, it struggles to scale to high-dimensional problems, leading to increased use of deep learning for tractable synthesis of robot safety. Unfortunately, existing neural safety synthesis methods often lack convergence guarantees and solution interpretability. In this paper, we present Minimax Actors Guided by Implicit Critic Stackelberg (MAGICS), a novel adversarial reinforcement learning (RL) algorithm that guarantees local convergence to a minimax equilibrium solution. We then build on this approach to provide local convergence guarantees for a general deep RL-based robot safety synthesis algorithm. Through both simulation studies on OpenAI Gym environments and hardware experiments with a 36-dimensional quadruped robot, we show that MAGICS can yield robust control policies outperforming the state-of-the-art neural safety synthesis methods., Comment: Algorithmic Foundations of Robotics (WAFR) XVI

Published
2024

2. FLoRA: Enhancing Vision-Language Models with Parameter-Efficient Federated Learning

Author

Nguyen, Duy Phuong, Munoz, J. Pablo, and Jannesari, Ali

Subjects
Computer Science - Machine Learning, Computer Science - Artificial Intelligence
Abstract

In the rapidly evolving field of artificial intelligence, multimodal models, e.g., integrating vision and language into visual-language models (VLMs), have become pivotal for many applications, ranging from image captioning to multimodal search engines. Among these models, the Contrastive Language-Image Pre-training (CLIP) model has demonstrated remarkable performance in understanding and generating nuanced relationships between text and images. However, the conventional training of such models often requires centralized aggregation of vast datasets, posing significant privacy and data governance challenges. To address these concerns, this paper proposes a novel approach that leverages Federated Learning and parameter-efficient adapters, i.e., Low-Rank Adaptation (LoRA), to train VLMs. This methodology preserves data privacy by training models across decentralized data sources and ensures model adaptability and efficiency through LoRA's parameter-efficient fine-tuning. Our approach accelerates training time by up to 34.72 times and requires 2.47 times less memory usage than full fine-tuning., Comment: 10 pages, 11 figures

Published
2024

3. ISAACS: Iterative Soft Adversarial Actor-Critic for Safety

Author

Hsu, Kai-Chieh, Nguyen, Duy Phuong, and Fisac, Jaime Fernández

Subjects
Computer Science - Machine Learning, Computer Science - Robotics, Electrical Engineering and Systems Science - Systems and Control
Abstract

The deployment of robots in uncontrolled environments requires them to operate robustly under previously unseen scenarios, like irregular terrain and wind conditions. Unfortunately, while rigorous safety frameworks from robust optimal control theory scale poorly to high-dimensional nonlinear dynamics, control policies computed by more tractable "deep" methods lack guarantees and tend to exhibit little robustness to uncertain operating conditions. This work introduces a novel approach enabling scalable synthesis of robust safety-preserving controllers for robotic systems with general nonlinear dynamics subject to bounded modeling error by combining game-theoretic safety analysis with adversarial reinforcement learning in simulation. Following a soft actor-critic scheme, a safety-seeking fallback policy is co-trained with an adversarial "disturbance" agent that aims to invoke the worst-case realization of model error and training-to-deployment discrepancy allowed by the designer's uncertainty. While the learned control policy does not intrinsically guarantee safety, it is used to construct a real-time safety filter (or shield) with robust safety guarantees based on forward reachability rollouts. This shield can be used in conjunction with a safety-agnostic control policy, precluding any task-driven actions that could result in loss of safety. We evaluate our learning-based safety approach in a 5D race car simulator, compare the learned safety policy to the numerically obtained optimal solution, and empirically validate the robust safety guarantee of our proposed safety shield against worst-case model discrepancy., Comment: Accepted in 5th Annual Learning for Dynamics & Control Conference (L4DC), University of Pennsylvania

Published
2022

4. Enhancing Heterogeneous Federated Learning with Knowledge Extraction and Multi-Model Fusion

Author

Nguyen, Duy Phuong, Yu, Sixing, Muñoz, J. Pablo, and Jannesari, Ali

Subjects
Computer Science - Distributed, Parallel, and Cluster Computing, Computer Science - Cryptography and Security, Computer Science - Machine Learning
Abstract

Concerned with user data privacy, this paper presents a new federated learning (FL) method that trains machine learning models on edge devices without accessing sensitive data. Traditional FL methods, although privacy-protective, fail to manage model heterogeneity and incur high communication costs due to their reliance on aggregation methods. To address this limitation, we propose a resource-aware FL method that aggregates local knowledge from edge models and distills it into robust global knowledge through knowledge distillation. This method allows efficient multi-model knowledge fusion and the deployment of resource-aware models while preserving model heterogeneity. Our method improves communication cost and performance in heterogeneous data and models compared to existing FL algorithms. Notably, it reduces the communication cost of ResNet-32 by up to 50\% and VGG-11 by up to 10$\times$ while delivering superior performance., Comment: Accept at the 4th workshop on Artificial Intelligence and Machine Learning for Scientific Applications (AI4S), SC 23

Published
2022

6. Sim-to-Lab-to-Real: Safe Reinforcement Learning with Shielding and Generalization Guarantees

Author

Hsu, Kai-Chieh, Ren, Allen Z., Nguyen, Duy Phuong, Majumdar, Anirudha, and Fisac, Jaime F.

Subjects
Computer Science - Robotics, Computer Science - Machine Learning
Abstract

Safety is a critical component of autonomous systems and remains a challenge for learning-based policies to be utilized in the real world. In particular, policies learned using reinforcement learning often fail to generalize to novel environments due to unsafe behavior. In this paper, we propose Sim-to-Lab-to-Real to bridge the reality gap with a probabilistically guaranteed safety-aware policy distribution. To improve safety, we apply a dual policy setup where a performance policy is trained using the cumulative task reward and a backup (safety) policy is trained by solving the Safety Bellman Equation based on Hamilton-Jacobi (HJ) reachability analysis. In Sim-to-Lab transfer, we apply a supervisory control scheme to shield unsafe actions during exploration; in Lab-to-Real transfer, we leverage the Probably Approximately Correct (PAC)-Bayes framework to provide lower bounds on the expected performance and safety of policies in unseen environments. Additionally, inheriting from the HJ reachability analysis, the bound accounts for the expectation over the worst-case safety in each environment. We empirically study the proposed framework for ego-vision navigation in two types of indoor environments with varying degrees of photorealism. We also demonstrate strong generalization performance through hardware experiments in real indoor spaces with a quadrupedal robot. See https://sites.google.com/princeton.edu/sim-to-lab-to-real for supplementary material., Comment: Accepted to Special Issue on Risk-aware Autonomous Systems: Theory and Practice, Artificial Intelligence

Published
2022
Full Text
View/download PDF

8. Interactive Control Between Human and Omnidirectional Mobile Robot: A Vision-Based Deep Learning Approach

Author

Nguyen, The Co, Bui, Trung Nghia, Nguyen, Van Nam, Nguyen, Duy Phuong, Nguyen, Cong Minh, Nguyen, Manh Linh, Kacprzyk, Janusz, Series Editor, Gomide, Fernando, Advisory Editor, Kaynak, Okyay, Advisory Editor, Liu, Derong, Advisory Editor, Pedrycz, Witold, Advisory Editor, Polycarpou, Marios M., Advisory Editor, Rudas, Imre J., Advisory Editor, Wang, Jun, Advisory Editor, Nguyen, Thi Dieu Linh, editor, Verdú, Elena, editor, Le, Anh Ngoc, editor, and Ganzha, Maria, editor

Published
2023
Full Text
View/download PDF

12. Mechanisms Underlying the Suppression of IL-1β Expression by Magnesium Hydroxide Nanoparticles

Author

Ayaka Koga, Chuencheewit Thongsiri, Daisuke Kudo, Dao Nguyen Duy Phuong, Yoshihito Iwamoto, Wataru Fujii, Yoshie Nagai-Yoshioka, Ryota Yamasaki, and Wataru Ariyoshi

Subjects
magnesium hydroxide nanoparticles, macrophages, MAPK pathways, NF-κB pathways, innate immunity, dentistry, Biology (General), QH301-705.5
Abstract

In recent years, magnesium hydroxide has been widely studied due to its bioactivity and biocompatibility. The bactericidal effects of magnesium hydroxide nanoparticles on oral bacteria have also been reported. Therefore, in this study, we investigated the biological effects of magnesium hydroxide nanoparticles on inflammatory responses induced by periodontopathic bacteria. Macrophage-like cells, namely J774.1 cells, were treated with LPS derived from Aggregatibacter actinomycetemcomitans and two different sizes of magnesium hydroxide nanoparticles (NM80/NM300) to evaluate their effects on the inflammatory response. Statistical analysis was performed using an unresponsive Student’s t-test or one-way ANOVA followed by Tukey’s post hoc test. NM80 and NM300 inhibited the expression and secretion of IL-1β induced by LPS. Furthermore, IL-1β inhibition by NM80 was dependent on the downregulation of PI3K/Akt-mediated NF-κB activation and the phosphorylation of MAPK molecules such as JNK, ERK1/2, and p38 MAPK. By contrast, only the deactivation of the ERK1/2-mediated signaling cascade is involved in IL-1β suppression by NM300. Although the molecular mechanism involved varied with size, these results suggest that magnesium hydroxide nanoparticles have an anti-inflammatory effect against the etiologic factors of periodontopathic bacteria. These properties of magnesium hydroxide nanoparticles can be applied to dental materials.

Published
2023
Full Text
View/download PDF

14. Expert Elicitation Methodology in the Risk Analysis of an Industrial Machine

Author

Venditti, Tony, Tran, Nguyen Duy Phuong, Ngo, Anh Dung, Kacprzyk, Janusz, Series Editor, Pal, Nikhil R., Advisory Editor, Bello Perez, Rafael, Advisory Editor, Corchado, Emilio S., Advisory Editor, Hagras, Hani, Advisory Editor, Kóczy, László T., Advisory Editor, Kreinovich, Vladik, Advisory Editor, Lin, Chin-Teng, Advisory Editor, Lu, Jie, Advisory Editor, Melin, Patricia, Advisory Editor, Nedjah, Nadia, Advisory Editor, Nguyen, Ngoc Thanh, Advisory Editor, Wang, Jun, Advisory Editor, and Arezes, Pedro Miguel Ferreira Martins, editor

Published
2019
Full Text
View/download PDF

15. Magnesium Hydroxide Nanoparticles Inhibit the Biofilm Formation of Cariogenic Microorganisms

Author

Kentaro Okamoto, Daisuke Kudo, Dao Nguyen Duy Phuong, Yoshihito Iwamoto, Koji Watanabe, Yoshie Yoshioka, Wataru Ariyoshi, and Ryota Yamasaki

Subjects
magnesium hydroxide nanoparticles, dental caries, cariogenic microorganisms, biofilm inhibition, Chemistry, QD1-999
Abstract

Although various caries-preventive agents have been developed, dental caries is still a leading global disease, mostly caused by biological factors such as mutans streptococci. Magnesium hydroxide nanoparticles have been reported to exhibit antibacterial effects; however, they are rarely used in oral care practical applications. In this study, we examined the inhibitory effect of magnesium hydroxide nanoparticles on biofilm formation by Streptococcus mutans and Streptococcus sobrinus—two typical caries-causing bacteria. Three different sizes of magnesium hydroxide nanoparticles (NM80, NM300, and NM700) were studied, all of which inhibited biofilm formation. The results showed that the nanoparticles were important for the inhibitory effect, which was not influenced by pH or the presence of magnesium ions. We also determined that the inhibition process was mainly contact inhibition and that medium (NM300) and large (NM700) sizes were particularly effective in this regard. The findings of our study demonstrate the potential applications of magnesium hydroxide nanoparticles as caries-preventive agents.

Published
2023
Full Text
View/download PDF

18. A theoretical screening of phytochemical constituents from Millettia brandisiana as inhibitors against acetylcholinesterase.

Author

Van Nguyen, Hue, Ha, Nguyen Xuan, Nguyen, Duy Phuong, Pham, Tho Hoan, Nguyen, Minh Tho, and Thi Nguyen, Hue Minh

Abstract

Alzheimer's disease is one of the causes associated with the early stages of dementia. Nowadays, the main treatment available is to inhibit the actions of the acetylcholinesterase (AChE) enzyme, which has been identified as responsible for the disease. In this study, computational methods were used to examine the structure and therapeutic ability of chemical compounds extracted from Millettia brandisiana natural products against AChE. This plant is commonly known as a traditional medicine in Vietnam and Thailand for the treatment of several diseases. Furthermore, machine learning helped us narrow down the choice of 85 substances for further studies by molecular docking and molecular dynamics simulations to gain deeper insights into the interactions between inhibitors and disease proteins. Of the five top-choice substances, γ-dimethylallyloxy-5,7,2,5-tetramethoxyisoflavone emerges as a promising substance due to its large free binding energy to AChE and the high thermodynamic stability of the resulting complex. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

20. Dynamic Fuzzy Safety Analysis of an Industrial System

Author

Veditti, Tony, Tran, Nguyen Duy Phuong, Ngo, Anh Dung, Kacprzyk, Janusz, Series editor, Pal, Nikhil R., Advisory editor, Bello Perez, Rafael, Advisory editor, Corchado, Emilio S., Advisory editor, Hagras, Hani, Advisory editor, Kóczy, László T., Advisory editor, Kreinovich, Vladik, Advisory editor, Lin, Chin-Teng, Advisory editor, Lu, Jie, Advisory editor, Melin, Patricia, Advisory editor, Nedjah, Nadia, Advisory editor, Nguyen, Ngoc Thanh, Advisory editor, Wang, Jun, Advisory editor, and Arezes, Pedro, editor

Published
2018
Full Text
View/download PDF

22. A Semi-supervised Learning Method for Hybrid Filtering

Author

Do, Thi Lien, Nguyen, Duy Phuong, Kacprzyk, Janusz, Series editor, Pal, Nikhil R., Advisory editor, Bello Perez, Rafael, Advisory editor, Corchado, Emilio, Advisory editor, Hagras, Hani, Advisory editor, Kóczy, László T., Advisory editor, Kreinovich, Vladik, Advisory editor, Lin, Chin-Teng, Advisory editor, Lu, Jie, Advisory editor, Melin, Patricia, Advisory editor, Nedjah, Nadia, Advisory editor, Nguyen, Ngoc Thanh, Advisory editor, Wang, Jun, Advisory editor, Akagi, Masato, editor, Nguyen, Thanh-Thuy, editor, Vu, Duc-Thai, editor, Phung, Trung-Nghia, editor, and Huynh, Van-Nam, editor

Published
2017
Full Text
View/download PDF

25. The role of State Forest Enterprises in the payments for Forest Environmental Services Programme in Vietnam

Author

Florence Milan, Tran Thi Thu Huong, Chu Thai Hoanh, Diana Suhardiman, Nguyen Duy Phuong, and Manfred Zeller

Subjects
environmental services, intermediaries, services providers, transaction costs, Agriculture
Abstract

To promote pro-poor payments for environmental services, it is necessary to identify institutional options that reduce transaction costs and organisational problems associated with establishing and maintaining contracts with small-scale environmental service providers. This study examined the dual functionality of state forest enterprises (SFEs) in the implementation of the Payments for Forest Environmental Services (PFES) Program in Vietnam. We considered whether SFEs’ involvement in the programme could reduce transaction costs and organisational problems. Data were collected from Tu Ly SFE in Hoa Binh province, northern Vietnam and from implementing agencies at various institutional levels. A survey of households participating in the SFE loan programme, and two stakeholder workshops were executed in 2014. The results revealed that Tu Ly SFE plays an important role in the livelihood of many farmers. A SWOT analysis exhibited SFEs’ advantage over other state agencies in implementing national forest management programmes as there are fewer parties involved with greater autonomy and outreach in the district. This study proposes the acknowledgment of SFEs as environmental service providers in their own forestlands and to use SFEs as intermediaries in the Payments for Forest Environmental Services Programme activities.

Published
2017

26. PHOTOLUMINESCENCE OF ZnO NANOSTRUCTURE PREPARED BY CATALYST - ASSISTED VAPOR - LIQUID - SOLID TECHNIQUE

Author

Tran Thi Quynh Hoa, Ta Dinh Canh, Nguyen Ngoc Long, Nguyen Viet Tuyen, and Nguyen Duy Phuong

Subjects
Photoluminescence, ZnO nanostructure, vapor-liquid-solid mechanism, Technology (General), T1-995, Science (General), Q1-390
Abstract

ZnO semiconductor nanostructures have been synthesized by thermal evaporation of mixture of ZnO and graphite powders. The thin layer of gold coated on Si substrates was used as a catalyst. The structure analysis shows high crystallinity of ZnO, their preferred orientation along the (0 02) plane of the wurtzite phase and their chemical purity. The scanning electron microscopy (SEM) images of products indicate that ZnO nanowires have a diameter of about 40 - 150 nm and a length of up to tens of micrometers. The morphology and structure of ZnO nanowires and nanorods depend on the thicknesses of the Au layers. The fact that Au nanoparticles are located at the tips of the nanowires represents a strong evidence for a growth process dominated by the vapor - liquid - solid mechanism. The low temperature photoluminescence spectra of the ZnO nanowires indicate a group of the ultraviolet narrow peaks and a blue - green very broad peak at 500 nm.

Published
2017
Full Text
View/download PDF

28. Development of a Dot-Elisa Assay for Diagnosis of Southern Rice Black-Streaked Dwarf Disease in the Field

Author

Nguyen Duy Phuong, Dam Quang Hieu, Pham Xuan Hoi, Ha Viet Cuong, Pham Thu Hang, Bui Thi Thu Huong, Do Thi Hanh, and La Duc Duy

Subjects
Pharmacology (medical)
Abstract

Outbreaks of the Southern rice black-streaked dwarf virus (SRBSDV) have caused significant losses in many rice-growing areas in Vietnam, especially in both North and Central Vietnam in recent years. To detect the virus, traditional reverse transcription polymerase chain reaction (RT-PCR) methodology and immunoassays are currently employed. RT-PCR is accurate but requires expensive chemicals and instruments, as well as complex procedures that limit its applicability for field tests. To develop a cheaper, simpler, and reliable SRBSDV diagnosis assay based on the dot-enzyme-linked immunosorbent assay (dot-ELISA) method, anti-SRBSDV polyclonal antibodies were produced by using the antigens derived from the P10 coat protein of SRBSDV, which was achieved from a previous study. The IgG antibody purified from the antiserum of recombinant P10-immunized mice by protein A-agarose affinity chromatography could specifically detect both the target protein and SRBSDV at a dilution of 1:100000. In the trial test of SRBSDV diagnosis, the dot-ELISA assay using the obtained anti-SRBSDV antibody showed an accuracy rate of 90.9% in comparison with the standard RT-PCR assay. These results are important premises for the large-scale application of dot-ELISA assay for SRBSDV diagnosis in order to protect rice crops against viral disease damage.

Published
2022
Full Text
View/download PDF

29. Functional characterization of the \(\textit{OsSWEET13 }\) promoter involved in the infection of \(\textit{ Xanthomonas oryzae }\) pv. \(\textit{oryzae (Xoo) }\) in rice cultivar TBR225

Author

Pham Phuong Ngoc, Tran Lan Dai, Do Thi Hanh, Nguyen Quang Huy, and Nguyen Duy Phuong

Subjects
Psychiatry and Mental health
Abstract

Xanthomonas oryzae pv. oryzae (Xoo) causes severe bacterial leaf blight (BLB) disease to many Vietnamese major rice cultivars, including the TBR225. OsSWEET13 belongs to group III of the OsSWEET gene family encoding sugar transport proteins, which is considered one of the “susceptibility” genes (S genes) necessary for BLB disease. In this study, the rice cultivar TBR225 was determined to be susceptible to 19/20 Vietnamese Xoo isolates collected from the Northern provinces. Two of the three tested isolates (VXO_60 and VXO_96 isolates) were shown to up-regulate OsSWEET13 upon the Xoo infection of the TBR225 cultivar. The TBR225 OsSWEET13 promoter was isolated for sequencing analysis. The isolated DNA fragment was 615 bp in size, contained an effector binding element (EBE) PthXo2 that was recognized by the type III-secretory transcription activator-like (TAL) proteins of the Xoo. This promoter showed a similarity of more than 99% to the published OsSWEET13 promoter sequences (AP014967.1 and CP018167.1). Our findings are basic for the generation of highyielding rice varieties with resistance to BLB disease by genetic engineering in Vietnam.

Published
2022
Full Text
View/download PDF

30. In silico validation revealed the role of SCN5A mutations and their genotype–phenotype correlations in Brugada syndrome

Author

Pham, Hung Manh, primary, Nguyen, Duy Phuong, additional, Ta, Thanh Dat, additional, Le, Thi Phuong, additional, Phan, Phong Hai, additional, Trinh, Hoai An, additional, Tran, Tuan Viet, additional, Luong, Thi Lan Anh, additional, Nguyen, Ha Minh, additional, Bui, The‐Hung, additional, Tran, Thinh Huy, additional, Ta, Thanh Van, additional, and Tran, Van‐Khanh, additional

Published
2023
Full Text
View/download PDF

31. Magnesium Hydroxide Nanoparticles Kill Exponentially Growing and Persister Escherichia coli Cells by Causing Physical Damage

Author

Yohei Nakamura, Kaede Okita, Daisuke Kudo, Dao Nguyen Duy Phuong, Yoshihito Iwamoto, Yoshie Yoshioka, Wataru Ariyoshi, and Ryota Yamasaki

Subjects
magnesium hydroxide nanoparticle, Escherichia coli, sterilization, persister, Chemistry, QD1-999
Abstract

Magnesium hydroxide nanoparticles are widely used in medicinal and hygiene products because of their low toxicity, environment-friendliness, and low cost. Here, we studied the effects of three different sizes of magnesium hydroxide nanoparticles on antibacterial activity: NM80, NM300, and NM700. NM80 (D50 = 75.2 nm) showed a higher bactericidal effect against Escherichia coli than larger nanoparticles (D50 = 328 nm (NM300) or 726 nm (NM700)). Moreover, NM80 showed a high bactericidal effect against not only exponential cells but also persister cells, which are difficult to eliminate owing to their high tolerance to antibiotics. NM80 eliminated strains in which magnesium-transport genes were knocked out and exhibited a bactericidal effect similar to that observed in the wild-type strain. The bactericidal action involved physical cell damage, as confirmed using scanning electron microscopy, which showed that E. coli cells treated with NM80 were directly injured.

Published
2021
Full Text
View/download PDF

34. Household opportunity costs of protecting and developing forest lands in Son La and Hoa Binh Provinces, Vietnam

Author

Le Ngoc Lan, Dennis Wichelns, Florence Milan, Chu Thai Hoanh, and Nguyen Duy Phuong

Subjects
bamboo, cassava, feasibility, maize, payment rate, pes, pfes, Political institutions and public administration (General), JF20-2112
Abstract

Vietnam has pilot-tested a payment for forest environmental services (PFES) program in an effort to restore and protect forest areas, some of which have been severely degraded by the excessive cutting of trees by small-scale farmers planting annual crops on steep, sloping lands. The pilot program implemented in southern Vietnam seems to be successful, yet the program in northern Vietnam has not produced the desired rates of planting and maintaining forest areas. The reasons for these mixed results include differences in socio-economic characteristics and also the production and marketing opportunities available to rural households in the project areas. To gain insight regarding program participation, we examine the household-level opportunity costs of planting and ­maintaining small plots of forest trees in northern Vietnam. We find that small-scale farmers in Hoa Binh Province, with limited financial resources, prefer the annual revenue stream provided by crops such as maize and cassava, rather than waiting for 7 years to obtain revenue from a forest planting. Farmers in Son La Province, with limited access to markets, prefer annual crops because they are not able to sell bamboo shoots and other forest products harvested from their small plots. In both provinces, the payments offered for planting and maintaining forest trees are smaller than the opportunity costs of planting and harvesting annual crops. Thus, most households likely would choose not to participate in the PFES program, at current payment rates, if given the opportunity to decline.

Published
2016
Full Text
View/download PDF

35. Production of peptide-specific antibody against protein P10 of Southern rice black-striked dwarf virus

Author

Do Thi Hanh, Pham Thu Hang, Nguyen Thanh Ha, Nguyen Thi Thu Ha, Phung Thi Thu Huong, Pham Xuan Hoi, and Nguyen Duy Phuong

Abstract

Virus Southern rice black-striked dwarf virus (SRBSDV) disease caused serious damage rice growing areas in Northern and Central Vietnam over the past decade. While the application of SRBSDV diagnostic methods based on the Reverse transcription polymerase chain reaction (RT-PCR) technique was impossible due to technical complexity, simpler SRBSDV diagnostic techniques using specific antibody have not yet been developed in Vietnam. The biggest difficulty right now was the absence of commercial specific antibodies against SRBSDV. To develop diagnostic techniques by enzyme-linked immunosorbent assay (ELISA) for SRBSDV detection, in a previous study, we created antibodies against SRBSDV from the 66 kDa recombinant SRBSDV protein P10 expressed in E. coli; the obtained antibodies had a titer of 1:5000 dilution. Here, we continued to produce polyclonal antibodies against SRBSDV from small antigenic peptide (PASTTDVTHYGGY) derived from the P10 envelope protein, which was consevative in Vietnamese SRBSDV population. Titer of the purified IgG antibody was exmined using Dot enzyme-linked immunosorbent assay (Dot-ELISA) which showed a titer of 1:40000 dilution. The specific binding between anti-peptide IgG antibodies diluted at 1:40000 and the recombinant P10 protein in E. coli extraction was confirmed by using western blotting. In Dot-ELISA, our antibodies could distinguish between the SRBSDV-infected and non-infected rice samples. Our research results open up a new opportunity for developing the rapid diagnosis Southern rice black-striked dwarf virus membrane-type kit in Vietnam.

Published
2022
Full Text
View/download PDF

37. Generation of Synthetic Peptide-Specific Antibody for the Development of A Southern Rice Black-Streaked Dwarf Virus Diagnostic Test

Author

Nguyen Duy Phuong, Nguyen Van Cuu, Phung Thi Thanh Huong, Pham Xuan Hoi, Do Thi Hanh, and Nguyen Anh Minh

Subjects
chemistry.chemical_classification, Specific antibody, chemistry, Southern rice black-streaked dwarf virus, Diagnostic test, Peptide, Biology, Virology
Abstract

Southern rice black-streaked dwarf virus (SRBSDV) causes severe epidemical disease on rice with the infected area up to millions of hectares in South China and North and Central of Vietnam. So far, there are no effective, cheap, quick, and practicable methods for diagnosing SRBSDV. The conventional RT-PCR technique is the most popular method for detecting SRBSDV with high accuracy. However, it is hard to apply this method for large-scale SDBSDV diagnosis because of the requirements of expensive reagents and instruments, as well as complex procedures. Meanwhile, SRBSDV diagnostic techniques based on antigen detection have outstanding advantages due to their low cost, easy manipulation, and wide application possibility. Today, there are still no commercially available specific antibodies to SRBSDV. In a previous study, to develop the SRBSDV diagnostic technique by the ELISA technique, a SRBSDV specific antibody was generated by a recombinant P10 envelope protein (66kDa), which has a titer of 1:5,000. In this study, we continued to study the production of SRBSDV specific polyclonal antibodies from small antigen–rich peptides from the SRBSDV P10 envelope protein. The resulting purified antibody can specifically bind to the P10 protein and at the diluted concentration of 1:100,000 it can detect SRBSDV in infected rice samples via the dot-blot technique. Our research results open up new opportunities for proactive antibodies to develop a SRBSDV membrane rapid diagnostic kit.

Published
2021
Full Text
View/download PDF

43. Study on tuberization of Rehmannia glutinosa (Gaertn.) Libosch

Author

Vu Hoai Sam, Duong Thi Ngoc Anh, Nguyen Thi Huong, Nguyen Thi Xuyen, Nguyen Minh Tuyen, Phan Thuy Hien, and Nguyen Duy Phuong

Subjects
Traditional medicine, fungi, food and beverages, Biology, Rehmannia glutinosa, biology.organism_classification
Abstract

Rehmannia glutinosa (Gaertn.) Libosch. is an herbal plant, which belongs to the Srcophulariaceae family, containing the main active ingredients such as catalpol and verbacoside in its root tubers. In traditional medicine, R. glutinosa tubers have been used in the fresh or dried tuber root or the prepared rehamannia root. They not only possess the comprehensive pharmacological actions in the blood system, endocrine system but also used mainly for anti-tumor treament, immune-enhancement, anti-diabetes, treament for concretion in the urinary tract, etc. R. glutinosa is naturally distributed in China, Korea and Japan. This species was introduced into Viet Nam since 1958 and then planted widely in many the Northern plain and midland provinces. In Vietnam, R. glutinosa produces flowers without seeds, therefore the plant has been mainly propagated by slicing tubers. In this work, we investigated the effect of some plant hormones and sucrose contents on the ability to producing microtubers of R. glutinosa. Experiments were establishmented on the 1/4 MS medium supplemented with 50g/L sucrose. Results showed that auxin (IBA, NAA) had no effect on the in vitro tuber formation of R. glutinosa. The efficiency of using the single BAP or PP333 was low. The highest in vitro tuberization rate of R. glutinosa obtained on the medium supplemented with the combination of BAP (1.0 mg/L) and PP333 (0.3 mg/L), reached 83.33% and the number of tubers/plant was 5.58. The optimal sucrose concentration for increasing the diameter and weight of microtubers was 70 g/L. 100% of plants with tuber-roots survived in the nursery and thrived on the field

Published
2020
Full Text
View/download PDF

46. DETERMINING A MEROMORPHIC FUNCTION BY ITS PREIMAGES OF FINITE SETS.

Author

Vu Hoai An, Ha Huy Khoai, and Nguyen Duy Phuong

Subjects
MEROMORPHIC functions, SET functions, MULTIPLICITY (Mathematics)
Abstract

We give some sufficient conditions for the zero set of a polynomial to be a unique range set for meromorphic functions, in cases of ignoring multiplicity and with m-truncated multipilicity. As consequences, we obtained some previous results of Yi ([23]). [ABSTRACT FROM AUTHOR]

Published
2023

47. Synthesis of Chitosan Stabilized Silver Nanoparticles and Evaluation of the in vitro Antibacterial Activity Against Xanthomonas oryzae pv. oryzae Causing Blight Disease of Rice

Author

Nguyen Thi Phuong Hue, Hoang Thi Giang, Le Trong Duc, Vu Thi Huyen, Le Thi Hien, Chu Duc Ha, Nguyen Thanh Ha, Nguyen Duy Phuong, Le Thi Van, and Le Huy Ham

Subjects
Chitosan, chemistry.chemical_compound, biology, chemistry, Xanthomonas oryzae pv. oryzae, food and beverages, Blight, biology.organism_classification, Antibacterial activity, Silver nanoparticle, In vitro, Microbiology
Abstract

Bacterial blight is one of the most devastating rice diseases that cause huge economic loss worldwide. The cause of rice blight is Gram negative bacteria Xanthomonas oryzae pv. oryzae (X. oryzae pv. Oryzae). Since both silver nanoparticles and chitosan have antibacterial, antifungal and growth-stimulating effect, this work has focused on synthesizing chitosan stabilized silver nanoparticles (AgCSs) with small sizes and in vitro evaluating antibacterial activity against X. oryzae pv. oryzae bacteria. AgCSs were chemically synthesized by reducing silver nitrate by borohydride sodium in the presence of chitosan with optimization of the concentration of the reactants. AgCSs were characterized by UV/vis absorption spectra, field emission scanning electronic microscopy (FESEM), ImageJ software, zeta potential measurement, Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction. AgCSs have spherical configuration and narrow size distributions with different average sizes from 15 nm to 25 nm depending on the initial concentration of silver nitrate. All AgCSs colloidal systems were stable and exhibited no tendency for coagulation more than 5 months. It was the first time that chitosan-stabilized silver nanoparticles were assessed the in vitro antibacterial activity against bacterial blight VXO_281 strain. The disc diffusion method demonstrated that the smallest size silver nanoparticles (AgCS1) showed high antibacterial effect against the X. oryzae pv. oryzae VXO_281 strain with a concentration of more than 5 µg/mL and the inhibition zone was dose-dependent. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of AgCS1 against X. oryzae pv. oryzae VXO_281 were 2.5 µg/mL and 20 µg/mL, respectively.

Published
2021
Full Text
View/download PDF

48. Design and transfer of OsSWEET14-editing T-DNA construct to bac thom 7 rice cultivar

Author

Nguyen Duy Phuong, Nguyen Thi Thu Ha, Cao Le Quyen, Pham Xuan Hoi, Pham Thi Van, Vu Hoai Sam, Phung Thi Thu Huong, and Nguyen Thanh Ha

Subjects
Genetics, Psychiatry and Mental health, Transfer (group theory), food and beverages, DNA construct, Cultivar, Biology
Abstract

Bac thom 7 rice (BT7 rice) is one of the major elite rice cultivars in Vietnam with superior productivity and quality but very susceptible to bacterial leaf blight caused by Xanthomonas oryzae pv. oryzae. The gene OsSWEET14, belonging to the OsSWEET family which encodes sugar transport proteins, is considered to be a susceptible gene involved in the virulence of Xoo. At least three cis-elements (EBE - Effector-binding element), including Tal5, PthXo3 and AvrXa7 on BT7 OsSWEET14 promoter, bind specifically to well-known transcription activator–like effectors (TALEs) of many Asian Xoo bacterium strains. In this study, a T-DNA construct which expressed the protein-RNA complex CRISPR/Cas for editing three EBEs position on the OsSWEET14 promoter was designed. The recombinant binary vector was tested by PCR, restriction enzyme and finally sequencing and then successfully transferred to Bac thom 7 rice through Agrobacterium tumefaciens. 28 of 30 hygromycin-resistant regenerated rice lines that grew and developed normally under nethouse conditions were selected by PCR with specific primers. Among these, twelve transgenic rice lines were identified carrying one copy of the T-DNA construct. The presence of CRISPR/Cas9-induced mutations of the targeted promoter in the transgenic plants were confirmed by T7EI assay. These results provide the basis to determine the role of OsSWEET14 in the susceptibility of Bac thom 7 rice to Xanthomonas oryzae pv. oryzae -caused disease, towards the further goal of generating an improved Bac thom 7 rice variety with broad-spectrum bacterial leaf blight resistance using CRISPR/Cas9 technology.

Published
2021
Full Text
View/download PDF

50. FUNCTIONAL CHARACTERIZATION OF THE OsSWEET13 PROMOTER INVOLVED IN THE INFECTION OF Xanthomonas oryzae pv. oryzae (Xoo) IN RICE CULTIVAR TBR225.

Author

Pham Phuong Ngoc, Tran Lan Dai, Do Thi Hanh, Nguyen Quang Huy, and Nguyen Duy Phuong

Abstract

Xanthomonas oryzae pv. oryzae (Xoo) causes severe bacterial leaf blight (BLB) disease to many Vietnamese major rice cultivars, including the TBR225. OsSWEET13 belongs to group III of the OsSWEET gene family encoding sugar transport proteins, which is considered one of the "susceptibility" genes (S genes) necessary for BLB disease. In this study, the rice cultivar TBR225 was determined to be susceptible to 19/20 Vietnamese Xoo isolates collected from the Northern provinces. Two of the three tested isolates (VXO_60 and VXO_96 isolates) were shown to up-regulate OsSWEET13 upon the Xoo infection of the TBR225 cultivar. The TBR225 OsSWEET13 promoter was isolated for sequencing analysis. The isolated DNA fragment was 615 bp in size, contained an effector binding element (EBE) PthXo2 that was recognized by the type III-secretory transcription activator-like (TAL) proteins of the Xoo. This promoter showed a similarity of more than 99% to the published OsSWEET13 promoter sequences (AP014967.1 and CP018167.1). Our findings are basic for the generation of highyielding rice varieties with resistance to BLB disease by genetic engineering in Vietnam. [ABSTRACT FROM AUTHOR]

Published
2022
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results