Unexpected cases in field diagnosis of African swine fever virus in Vietnam: The needs consideration when performing molecular diagnostic tests

Background: The first confirmed case of African swine fever (ASF) in Vietnam was reported officially in February 2019. To date, ASF virus (ASFV) have been detected in 63/63 provinces in Vietnam. Currently, real-time polymerase chain reaction (PCR) is considered to be a powerful tool for viral detection in field samples, including ASFV. However, some recent reports have suggested that mismatches in primer and probe binding regions may directly affect real-time PCR qualification, leading a false-negative result.Aim: This study aims to further examine a conflicting result obtained from two OIE recommended methods, conventional PCR and real-time PCR, for ASFV detection.Methods: Two ASF suspected pigs from different provinces in the north of Vietnam were selected for this study based on clinical signs and postmortem lesions. The different results obtained by OIE-recommended conventional PCR and real-time PCR were further analyzed by the Sanger sequencing method and virus isolation in combination with hemadsorption (HAD) test using porcine alveolar macrophages cells.Results: The results showed that when the primer sequence matched perfectly with the sequences of field isolates, a mutation in probe binding region was found, indicating that a single mismatch in the probe binding site may cause a false-negative result by real-time PCR in detecting ASFV in clinical samples in Vietnam. An agreement between conventional PCR, using PPA1/PPA2 primers and two golden standard methods, virus isolation in combination with HAD assay, and sequencing method was observed in this study.Conclusion: A single mismatch in the probe binding site caused a failse-negative result by realtime PCR method in field diagnosis of ASFV. The needs consideration when selecting the appropriate molecular diagnostic methods is based on the current databases of ASFV sequences,  particularly for epidemiological surveillance of ASF. Keywords: African swine fever, PCR, Pigs, Real-time PCR, Vietna

DETERMINATION THE PRIORITY OF FACTORS INFLUENCING OVERSEAS INVESTMENT DESTINATIONS OF BUSINESSES USING AN ANALYTIC HIERARCHY PROCESS METHOD

Because of the great benefits overseas investment brings, countries and businesses are increasingly concerned with the question of an ideal investment destination. Many studies have shown that, factors of the consumption market, the infrastructure and resources, economic and political environment have a significant impact on the decision to choose an investment location, however the priority order of these factors are different for various research spaces. By studying the specific case of Viettel Group - one of the largest telecommunications groups in Vietnam that is having many international investment activities in recent years, the study has been verified the priority order of factors influencing the decision to choose an overseas investment location of this corporation. The research outcomes show that the group of factors that have the most influence on investment decisions is the group "Consumption market", more specifically, the sub-factor "Market Size" is considered more than the others.    Keywords: Investment Destinations, Foreign Investment Decision, Analytic Hierarchy Process

Somatic embryogenesis and plant regeneration from leaf callus with genetic stability validation using SCoT markers in Paramignya trimera, a medicinal plant native to Vietnam

Xao tam phan (Paramignya trimera (Oliv.) Guillaum) is a medicinal plant native to Vietnam, that is renowned for its therapeutic properties, particularly for the treatment of various ailments, including cancer. This study investigated in vitro propagation of P. trimera through somatic embryogenesis and shoot organogenesis using leaf callus. Various culture media, plant growth regulators, malt extract, and carbon sources were evaluated to optimize callus induction and somatic embryo formation from leaf explants. DNA barcoding confirmed 96.96% to 100% homology with P. trimera specimens from Khanh Hoa province, Vietnam. The highest callus formation rate, reaching 100%, was observed in one-year-old explants cultured in Woody Plant Medium (WPM) supplemented with 2.0 mg L-1 naphthaleneacetic acid (NAA) and 0.2 mg L-1 benzylaminopurine (BAP) in the dark for over six weeks. In WPM supplemented with 30 g L-1 sucrose, 4.0 mg L-1 BAP, and 500 mg L-1 malt extract, globular stage embryos developed into embryoids and shoots and buds clumped at 10 and 18 weeks, respectively. Shoot organogenesis was observed in WPM supplemented with 30 g L-1 sucrose and 0.07 mg L-1 thidiazuron (TDZ) after 18 weeks of culture. Genetic fidelity assessments using 12 SCoT markers indicated that in vitro plantlets were homologous to the mother plant. This study provides a viable method for the conservation and sustainable cultivation of Xao tam phan, ensuring a stable supply of this valuable medicinal resource

Brza serotipizacija virusa afričke kuge svinja zasnovana na analizi kratkih fragmenata EP402R gena koji kodira CD2-like protein

The first confirmed case of African swine fever (ASF) in Vietnam was officially reported in February 2019. To date, the ASF virus (ASFV) has been detected in all 63 cities/provinces in Vietnam. In order to get a better understanding of the potential role of the EP402R gene in a grouping of ASFV serotypes, thirty ASFV sequences of EP402R genes (accession numbers: MN711757-86) from North Central Coast of Vietnam and 68 well-known references of serotype groups from previous studies were further analyzed. Interestingly, we found that a short fragment of 90 nucleotides was very typical for 8 serological groups of ASFVs. A primer set was designed to amplicon the short fragment of 90 nucleotides using the Primer3 program to establish a simplified method for the serotyping of ASFV. Our results indicated that phylogenetic analysis of the short fragment (90 nucleotides) of the EP402R gene is a very specific and useful method for ASFV serotyping when compared to the previous method using a long fragment (816 nucleotides) of this gene and well-known serotype references based on haemadsorption inhibition (HAI) assay.Prvi potvrđen slučaj afričke kuge svinja (ASF) u Vijetnamu bio je zvanično prijavljen u februaru 2019. godine. Do danas, ASF virus (ASFV) je detektovan u 63 provincije Vijetnama. Radi boljeg razumevanja potencijalne uloge EP402R gena u grupisanju ASFV serotipova, analizirano je trideset ASFV sekvenci EP402R gena (pristupni brojevi: MN711757-86) poreklom iz Centralne severne obale Vijetnama i 68 referentnih uzoraka serotip grupa koji su dobro poznati iz prethodnih studija. Interesantan je bio nalaz da je kratak fragment od 90 nukleotida bio tipičan za 8 seroloških grupa ASF virusa. Dizajniran je set prajmera sa ciljem amplifi kacije kratkih fragmenata (90 nukleotida), korišćenjem Primer3 programa, a za uspostavljanje jednostavne metode serotipiziranja ASFV. Rezultati ukazuju da je fi logenetska analiza kratkih fragmenata (90 nukleotida) EP402R gena je veoma specifična i predstavlja korisnu metodu serotipizacije ASFV u poređenju sa prethodno opisanim metodama koje su koristile duge fragmente (816 nukleotida) ovog gena kao i dobro poznate referentne serotipove dobijene metodom inhibicije hemadsorbcije

Synthesis and application of Fe3O4/GO/PVP composite material for methylene blue adsorption

In this study, Fe3O4/GO/PVP (FGP) was successfully synthesized and efficiently applied for absorbing methylene blue. First, GO was synthesized by Hummer’s method from waste home-batteries. The chemical co-precipitation method was used to fabricate Fe3O4/GO from a mixture solution of GO, Fe3+, Fe2+. Polyvinylpyrrolidone PVP was selected to functionalize Fe3O4/GO and form Fe3O4/GO/PVP for improving dispersibility purpose in aqueous solution. The obtained Fe3O4/GO/PVP was characterized by XRD, FT-IR, BET, FE-SEM, UV-Vis techniques. Moreover, the effecting factors as pH, time adsorption, initial concentration of methylene blue were conducted. Adsorption isotherm models were also identified. The results showed that specific surface area of FGP-3 was 70.0 m2.g-1, the Freundlich isotherm model was suitable and the Dubinin - Radushkevich isotherm model showed that the process was physical adsorption. The maximum capacity (qmax) was 30.4 mg.g-1. These findings prove Fe3O4/GO/PVP as an inexpensive and efficient adsorbent for removal of cationic dyes

Network Coding with Multimedia Transmission and Cognitive Networking: An Implementation based on Software-Defined Radio

Network coding (NC) is considered a breakthrough to improve throughput, robustness, and security of wireless networks. Although the theoretical aspects of NC have been extensively investigated, there have been only few experiments with pure NC schematics. This paper presents an implementation of NC under a two-way relay model and extends it to two\ua0non-straightforward scenarios: (i) multimedia transmission with layered coding and multiple-description coding, and (ii) cognitive radio with Vandermonde frequency division multiplexing (VFDM). The implementation is in real time and based on software-defined radio (SDR). The experimental results show that, by combining NC and source coding, we can control the quality of the received multimedia content in an on-demand manner. Whereas in the VFDM-based cognitive radio, the quality of the received content in the primary receiver is low (due to imperfect channel estimation) yet retrievable. Our implementation results serve as a proof for the practicability of network coding in relevant applications

Network Coding with Multimedia Transmission and Cognitive Networking: An Implementation based on Software-Defined Radio

Network coding (NC) is considered a breakthrough to improve throughput, robustness, and security of wireless networks. Although the theoretical aspects of NC have been extensively investigated, there have been only few experiments with pure NC schematics. This paper presents an implementation of NC under a two-way relay model and extends it to two non-straightforward scenarios: (i) multimedia transmission with layered coding and multiple-description coding, and (ii) cognitive radio with Vandermonde frequency division multiplexing (VFDM). The implementation is in real time and based on software-defined radio (SDR). The experimental results show that, by combining NC and source coding, we can control the quality of the received multimedia content in an on-demand manner. Whereas in the VFDM-based cognitive radio, the quality of the received content in the primary receiver is low (due to imperfect channel estimation) yet retrievable. Our implementation results serve as a proof for the practicability of network coding in relevant applications

Differential Infectivity of Human Neural Cell Lines by a Dengue Virus Serotype-3 Genotype-III with a Distinct Nonstructural Protein 2A (NS2A) Amino Acid Substitution Isolated from the Cerebrospinal Fluid of a Dengue Encephalitis Patient

Dengue encephalitis is considered as a severe but unusual clinical presentation of dengue infection. Limited molecular information is available on the neurotropism of dengue virus (DENV), highlighting the need for further research. During a dengue outbreak in Vietnam in 2013, two DENV-3 strains were isolated, in which one was isolated from cerebrospinal fluid (CSF) samples from a dengue encephalitis patient and another strain was isolated from a patient with classical dengue fever in Hai Phong, Vietnam. DENV serotype-3 (DENV-3) isolated from these samples belonged to genotype III, marking the first report of this genotype in the country at that time. Genetic variation between both strains was elucidated by using a full genome sequencing by next-generation sequencing (NGS). The infectivity of the isolated DENV-3 strains was further characterized using human and mouse neuronal cell lines. Phylogenetic analysis of the isolates demonstrated high homogeneity between the CSF-derived and serum-derived DENV-3, in which the full genome sequences of the CSF-derived DENV-3 presented a Thr-1339-Ile mutation in the nonstructural 2A (NS2A) protein. The CSF-derived DENV-3 isolate grew preferentially in human neuronal cells, with a significant proportion of cells that were positive for nonstructural 1 (NS1), nonstructural 4B (NS4B), and nonstructural 5 (NS5) antigens. These results suggest that NS2A may be a crucial region in the neuropathogenesis of DENV-3 and its growth in human neuronal cells. Taken together, our results demonstrate that a CSF-derived DENV-3 has unique infectivity characteristics for human neuronal cells, which might play a crucial role in the neuropathogenesis of DENV infection