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Contribution to Taxonomy and Distribution of the Genus Elaphropoda (Hymenoptera: Apidae: Apinae) in Vietnam

  • Nguyen, Minh Phuong;Tran, Ngat Thi;Nguyen, Dai Dac;Nguyen, Lien Thi Phuong
    • Animal Systematics, Evolution and Diversity
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    • v.32 no.2
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    • pp.118-122
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    • 2016
  • Taxonomic notes on the genus Elaphropoda Lieftinck, 1966 (Hymenoptera: Apidae) from Vietnam are presented. Two species of the genus are reported: Elaphropoda percarinata (Cockerell, 1930) was first recorded from Vietnam based on specimens collected from Ha Tinh province in 1998, and is reconfirmed with a specimens collected from Bac Kan province in the Northeastern part of the country in this study, and Elaphropoda khasiana (Schulz, 1906) is recorded from Vietnam for the first time. Redescriptions of the male of E. percarinata and the female of E. khasiana are given with illustrations.

CAN-Based Networked Control Systems: A Co-Design of Time Delay Compensation and Message Scheduling

  • Cac, Nguyen Trong;Hung, Nguyen Xuan;Khang, Nguyen Van
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.39B no.10
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    • pp.629-644
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    • 2014
  • The goal of this paper is to consider a co-design approach between time delay compensation and the message scheduling for CAN-Based Networked Control Systems (NCS). First we propose a hybrid priority scheme for the message scheduling in order to improve the Quality of Service (QoS). Second we present the way to calculate the closed-loop communication time delay and then compensate this time delay using the pole placement design method in order to improve the Quality of Control (QoC). The final objective is the implementation of a co-design which is the combination of the compensation for communication time delays and the message scheduling in order to have a more efficient NCS design.

Detecting smartphone user habits using sequential pattern analysis

  • Lu, Dang Nhac;Nguyen, Thu Trang;Nguyen, Thi Hau;Nguyen, Ha Nam;Choi, Gyoo Seok
    • International Journal of Internet, Broadcasting and Communication
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    • v.7 no.1
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    • pp.20-22
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    • 2015
  • Recently, the study of smart phone user habits has become a highly focused topic due to the rapid growth of the smart phone market. Indeed, sequential pattern analysis methods were efficiently used for web-based user habit mining long time ago. However, by means of simulations, it has been observed that these methods might fail for smart phone-based user habit mining. In this paper, we propose a novel approach that leads to a considerably increased performance of the traditional sequential pattern analysis methods by reasonably cutting off each chronological sequence of user logs on a device into shorter ones, which represent the sequential user activities in various periods of a day.

A New Dimeric Lignan from the Stems of Willughbeia edulis

  • Nguyen, Hai Xuan;Do, Truong Nhat Van;Le, Tho Huu;Dang, Phu Hoang;Nguyen, Mai Thanh Thi;Nguyen, Nhan Trung
    • Natural Product Sciences
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    • v.28 no.2
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    • pp.53-57
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    • 2022
  • As part of our continued study on the chemical constituents of Willughbeia edulis stems, a new dimeric lignan named edulignan (1) was isolated from its EtOAc-soluble extract. Based on NMR spectroscopic interpretation, the planar structure of 1 has been suggested to have two 2-substituted 4-chromanone subunits with different stereochemical configurations. In addition, the MS/MS analysis of the products obtained by acid-catalyzed hydrolysis of 1 was supportive of its structure. Unfornatually, the new compound 1 did not show 𝛼-glucosidase inhibitory activity with an IC50 value > 250 𝜇M.

A Hybrid Method Based on Genetic Algorithm and Ant Colony System for Traffic Routing Optimization

  • Thi-Hau Nguyen;Ha-Nam Nguyen;Dang-Nhac Lu;Duc-Nhan Nguyen
    • International Journal of Computer Science & Network Security
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    • v.23 no.8
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    • pp.85-90
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    • 2023
  • The Ant Colony System (ACS) is a variant of Ant colony optimization algorithm which is well-known in Traveling Salesman Problem. This paper proposed a hybrid method based on genetic algorithm (GA) and ant colony system (ACS), called GACS, to solve traffic routing problem. In the GACS, we use genetic algorithm to optimize the ACS parameters that aims to attain the shortest trips and time through new functions to help the ants to update global and local pheromones. Our experiments are performed by the GACS framework which is developed from VANETsim with the ability of real map loading from open street map project, and updating traffic light in real-time. The obtained results show that our framework acquired higher performance than A-Star and classical ACS algorithms in terms of length of the best global tour and the time for trip.

Applying Machine Learning approaches to predict High-school Student Assessment scores based on high school transcript records

  • Nguyen Ba Tien;Hoai-Nam Nguyen;Hoang-Ha Le;Tran Thu Trang;Chau Van Dinh;Ha-Nam Nguyen;Gyoo Seok Choi
    • International Journal of Internet, Broadcasting and Communication
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    • v.15 no.2
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    • pp.261-267
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    • 2023
  • A common approach to the problem of predicting student test scores is based on the student's previous educational history. In this study, high school transcripts of about two thousand candidates, who took the High-school Student Assessment (HSA) were collected. The data were estimated through building a regression model - Random Forest and optimizing the model's parameters based on Genetic Algorithm (GA) to predict the HSA scores. The RMSE (Root Mean Square Error) measure of the predictive models was used to evaluate the model's performance.

Detection of virulence, specific genes and antibiotic resistance of isolated Salmonella spp. strains from rabbits infected with salmonellosis

  • Huynh Van Chuong;Nguyen Minh Tuan;Nguyen Thi Nhu Anh;Le Thi Lan Phuong;Nguyen Xuan Hoa
    • Korean Journal of Veterinary Research
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    • v.63 no.2
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    • pp.16.1-16.6
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    • 2023
  • Salmonella spp. are pathogens involved in most salmonellosis in rabbits. This study examined Salmonella disease in rabbits raised in Thua Thien Hue, Vietnam. Two hundred and 56 rectal swabs of rabbits were taken, and a carrier rate of 33.98% was found. In addition, all the isolated Salmonella spp. strains were 100% motile; positive for H2S, catalase, Voges Proskauer, coagulase, citrate, maltose, and dextrose; and negative for indole, methyl red, urease, oxidase, sucrose, and lactose. The Kirby-Bauer method showed that these Salmonella strains were susceptible to doxycycline (93.2%), tetracycline (84.1%), and levofloxacin (65.9%). On the other hand, they were highly resistant to streptomycin (95.5%), ampicillin (93.2%), colistin (40.9%), and gentamicin (34.1%). Furthermore, polymerase chain reaction used to screen for virulence and specific genes of Salmonella strains showed that all Salmonella strains isolated carried InvA, fimA, and Stn.

Some characters of bacterial cellulases in goats' rumen elucidated by metagenomic DNA analysis and the role of fibronectin 3 module for endoglucanase function

  • Nguyen, Khanh Hoang Viet;Dao, Trong Khoa;Nguyen, Hong Duong;Nguyen, Khanh Hai;Nguyen, Thi Quy;Nguyen, Thuy Tien;Nguyen, Thi Mai Phuong;Truong, Nam Hai;Do, Thi Huyen
    • Animal Bioscience
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    • v.34 no.5
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    • pp.867-879
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    • 2021
  • Objective: Fibronectin 3 (FN3) and immunoglobulin like modules (Ig) are usually collocated beside modular cellulase catalytic domains. However, very few researches have investigated the role of these modules. In a previous study, we have sequenced and analyzed bacterial metagenomic DNA in Vietnamese goats' rumen and found that cellulase-producing bacteria and cellulase families were dominant. In this study, the properties of modular cellulases and the role of a FN3 in unique endoglucanase belonging to glycosyl hydorlase (GH) family 5 were determined. Methods: Based on Pfam analysis, the cellulases sequences containing FN3, Ig modules were extracted from 297 complete open reading frames (ORFs). The alkaline, thermostability, tertiary structure of deduced enzymes were predicted by AcalPred, TBI software, Phyre2 and Swiss models. Then, whole and truncated forms of a selected gene were expressed in Escherichia coli and purified by His-tag affinity column for assessment of FN3 ability to enhance enzyme activity, solubility and conformation. Results: From 297 complete ORFs coding for cellulases, 148 sequences containing FN3, Ig were identified. Mostly FN3 appeared in 90.9% beta-glucosidases belonging to glycosyl hydrolase family 3 (GH3) and situated downstream of catalytic domains. The Ig was found upstream of 100% endoglucanase GH9. Rarely FN3 was seen to be situated downstream of X domain and upstream of catalytic domain endoglucanase GH5. Whole enzyme (called XFN3GH5 based on modular structure) and truncate forms FN3, XFN3, FN3GH5, GH5 were cloned in pET22b (+) and pET22SUMO to be expressed in single and fusion forms with a small ubiquitin-related modifier partner (S). The FN3, SFN3 increased GH5 solubility in FN3GH5, SFN3GH5. The SFN3 partly served for GH5 conformation in SFN3GH5, increased modules interaction and enzyme-soluble substrate affinity to enhance SXFN3GH5, SFN3GH5 activities in mixtures. Both SFN3 and SXFN3 did not anchor enzyme on filter paper but exfoliate and separate cellulose chains on filter paper for enzyme hydrolysis. Conclusion: Based on these findings, the presence of FN3 module in certain cellulases was confirmed and it assisted for enzyme conformation and activity in both soluble and insoluble substrate.

Parenchymal-sparing anatomical hepatectomy based on portal ramification of the right anterior section: A prospective multicenter experience with short-term outcomes

  • Truong Giang Nguyen;Thanh Khiem Nguyen;Ham Hoi Nguyen;Hong Son Trinh;Tuan Hiep Luong;Minh Trong Nguyen;Van Duy Le;Hai Dang Do;Kieu Hung Nguyen;Van Minh Do;Quang Huy Tran;Cuong Thinh Nguyen
    • Annals of Hepato-Biliary-Pancreatic Surgery
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    • v.28 no.1
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    • pp.25-33
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    • 2024
  • Backgrounds/Aims: Parenchymal-sparing anatomical hepatectomy (Ps-AH) based on portal ramification of the right anterior section (RAS) is a new technique to avoid unnecessarily transecting too much liver parenchyma, especially in cases of major anatomical hepatectomy. Methods: We prospectively assessed 26 patients with primary hepatic malignancies having undergone major Ps-AH based on portal ramification of the RAS from August 2018 to August 2022 (48 months). The perioperative indications, clinical data, intra-operative index, pathological postoperative specimens, postoperative complications, and follow-up results were retrospectively evaluated. Results: Among the 26 patients analyzed, there was just one case that had intrahepatic cholangiocarcinoma The preoperative level of α-Fetoprotein was 25.2 ng/mL. All cases (100%) had Child-Pugh A liver function preoperatively. The ventral/dorsal RAS was preserved in 19 and 7 patients, respectively. The mean surgical margin was 6.2 mm. The mean surgical time was 228.5 minutes, while the mean blood loss was 255 mL. In pathology, 5 cases (19.2%) had microvascular invasion, and in the group of HCC patients, 92% of all cases had moderate or poor tumor differentiation. Six cases (23.1%) of postoperative complications were graded over III according to the Clavien-Dindo system, including in three patients resistant ascites or intra-abdominal abscess that required intervention. Conclusions: Parenchymal-sparing anatomical hepatectomy based on portal ramification of the RAS to achieve R0-resection was safe and effective, with favorable short-term outcomes. This technique can be used widely in clinical practice.

Evaluation of Hydrogen Sulfide Corrosion Inhibitors for Wet Gas Pipeline Steel

  • Huy, Vu Dinh;Thoa, Nguyen Thi Phuong;Phong, Tran Quoc;Hoang, Nguyen Thai
    • Corrosion Science and Technology
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    • v.4 no.3
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    • pp.95-99
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    • 2005
  • Wheel test and potentiodynamic polarization methods were used to evaluate the relative effectiveness of some hydrogen sulfide corrosion inhibitors for the wet gas pipeline API 5L grade X 65 steel. Five commercially corrosion inhibitors have been studied in the deoxygenated produced water solutions containing 10 ppm and 100 ppm of hydrogen sulfide. Based on the experiment results the steel corrosion inhibition mechanism in discussed and two most effective corrosion inhibitors are selected.