ƯƠNG GIỐNG CUA BIỂN (Scylla paramamosain) VỚI CÁC LOẠI THỨC ĂN VÀ MẬT ĐỘ KHÁC NHAU

This study aims to determine the appropriate feed type and stocking density to improve the survival rate and growth performance of mud crab crablet during the nursery stage. The study consisted of 2 experiments as follows: (1) Rearing crablets with different feed types (including commercial feed, artemia biomass and acetes biomass) and (2) rearing crablets at different stocking densities (including 100; 200; 300 and 400 inds/m2). All treatments were randomly set up in triplicate. The initial sizes of crablet were 3.24 ± 0.54 mm in length, 4.54 ± 0.79 mm in width and 0.018 ± 0.004 g in weight. The result showed that using acetes biomass gave the best results compared to other treatments. The survival rate was 58.8% and biomass was 118 inds/m2. The second experiment showed that rearing crablets at 100 inds/m2 reached the highest survival rate (90.7%) and biomass (91 inds/m2).Nghiên cứu nhằm xác định loại thức ăn và mật độ ương thích hợp để nâng cao tỷ lệ sống và tăng trưởng trong ương giống cua biển. Nghiên cứu gồm 2 thí nghiệm: (1) ương cua giống với các loại thức ăn khác nhau (thức ăn công nghiệp, artemia sinh khối và con ruốc sinh khối) và (2) ương cua giống với các mật độ khác nhau (100; 200; 300 và 400 con/m2). Các nghiệm thức được bố trí hoàn toàn ngẫu nhiên và được lặp lại 3 lần. Cua giống có chiều dài ban đầu là 3,24 mm, chiều rộng 4,54 mm và khối lượng 0,018 g. Kết quả thí nghiệm 1 cho thấy, khi sử dụng thức ăn con ruốc sinh khối cho kết quả tốt nhất về tỷ lệ sống (58,8%) và sinh khối đạt 118 con/m2. Thí nghiệm 2 cho thấy, khi ương cua ở mật độ 100 con/m2 cho kết tốt nhất về tỷ lệ sống (90,7%) và sinh khối đạt 91 con/m2

Chemical components and biological properties from acetone extracts of Conamomum vietnamense

Conamomum vietnamense is an endemic and rare species from Vietnam. The aim of this study is to determine the chemical compositions, antibacterial and antioxidant properties of the acetone extracts obtained from the different organs of this species for the first time. A total of 82 components were identified from the acetone extracts of leaf, flower, and rhizome of C. vietnamense using Gas chromatography–mass spectrometry (GC/MS) technique. Furthermore, the agar disk-diffusion method was also used to determine the antibacterial activity of the C. vietnamense extracts. Accordingly, the leaf extract was found to be effective against eight out of nine bacterial strains while the flower and rhizome extracts displayed activity against four out of nine tested bacteria. In addition, the three organs of C. vietnamense also possessed the high DPPH scavenging properties. The results of this study indicate that C. vietnamense extracts have the potential to be developed into pharmaceutical products in the future

Molecular cloning gene and nucleotide sequence of the gene encoding an endo-1,4-β-glucanase from Bacillus sp VLSH08 strain applying to biomass hydrolysis: Research article

Bacillus sp VLSH08 screened from sea wetland in Nam Dinh province produces an extracellular endo-1,4-beta-glucanase. According to the results of the classified Kit API 50/CHB as well as sequence of 1500 bp fragment coding for 16S rRNA gene of the Bacillus sp VLSH 08 strain showed that the taxonomical characteristics between the strain VLSH 08 and Bacillus amyloliquefaciene JN999857 are similar of 98%. Culture supernatant of this strain showed optimal cellulase activity at pH 5.8 and 60 Celsius degree and that was enhanced 2.03 times in the presence of 5 mM Co2+. Moreover, the gene encoding endo-1,4-beta-glucanase from this strain was cloned in Escherichia coli using pCR2.1 vector. The entire gene for the enzyme contained a 1500-bp single open reading frame encoding 500 amino acids, including a 29-amino acid signal peptide. The amino acid sequence of this enzyme is very close to that of an EG of Bacillus subtilis (EU022560.1) and an EG of Bacillus amyloliquefaciene (EU022559.1) which all belong to the cellulase family E2. A cocktail of enzyme containing this endo-1,4-beta-glucanase used for biomass hydrolysis indicated that the cellulose conversion attained to 72.76% cellulose after 48 hours.Chủng vi khuẩn Bacillus sp VLSH08 được tuyển chọn từ tập hợp chủng vi khuẩn phân lập ở vùng ngập mặn tỉnh Nam Định có khả năng sinh tổng hợp enzyme endo-1,4-beta-glucanase ngoại bào. Kết quả phân loại chủng vi khuẩn Bacillus sp VLSH08 bằng Kit hóa sinh API 50/CHB cũng như trình tự gen mã hóa 16S rRNA cho thấy độ tương đồng của chủng Bacillus sp VLSH08 và chủng Bacillus amyloliquefaciene JN999857 đạt 98%. Dịch lên men của chủng được sử dụng làm nguồn enzyme thô để nghiên cứu hoạt độ tối ưu của enzyme ở pH 5,8 và nhiệt đô 60oC. Hoạt tính enzyme tăng 2,03 lần khi có mặt 5 mM ion Co2+. Đồng thời, gen mã hóa cho enzyme endo-1,4-betaglucanase cũng được tách dòng trong tế bào Escherichia coli sử dụng vector pCR 2.1. Gen mã hóa cho enzyme này có chiều dài 1500 bp, mã hóa cho 500 axit amin, bao gồm 29 axit amin của chuỗi peptid tín hiệu. So sánh cho thấy trình tự gen endo-1,4-beta-glucanase của chủng Bacillus sp VLSH08 có độ tương đồng cao với enzyme này của chủng Bacillus subtilis (EU022560.1) và của chủng Bacillus amyloliquefaciene (EU022559.1). Tất cả các enzyme nhóm này đều thuộc họ cellulase E2. Enzyme của chủng này cũng đã được phối trộn với các enzyme khác tạo thành cocktail để thủy phân sinh khối cho kết quả cellulose bị thủy phân 72,76% sau 48 giờ

Broadcast Gossip Based Distributed Hypothesis Testing in Wireless Sensor Networks

We consider the scenario that N sensors collaborate to observe a single event. The sensors are distributed and can only exchange messages through a network to reach a consensus about the observed event. In this paper, we propose a very robust and simple method using broadcast gossip algorithm to solve the distributed hypothesis testing problem. The simulation result shows that our method has good performance and is very energy efficient comparing to existing methods

Ureaplasma urealyticum and Mycoplasma genitalium detection and sperm quality: A cross-sectional study in Vietnam

Background: Ureaplasma urealyticum (U. urealyticum) and Mycoplasma genitalium (M. genitalium) may colonize the male genital tract. However, the negative effects of these bacteria on overall sperm quality, including semen pH, sperm concentration, motility, morphology, and total sperm count remain unclear. Objective: This study aimed to determine the presence of genital U. urealyticum and M. genitalium in semen and evaluate the effect of these organisms on sperm quality. Materials and Methods: A cross-sectional study was conducted on 380 men from infertile couples at a tertiary university hospital from July 2017 to June 2018. Semen quality was analyzed according to the World Health Organization 2010 standard, and U. urealyticum and M. genitalium were detected in the semen samples using polymerase chain reaction. Results: 338 men (88.9%) presented with at least one abnormal semen parameter. The detection rates of U. urealyticum and M. genitalium were 16.05% and 0.79%, respectively. There was no significant difference between the Ureaplasma-positive group and the Ureaplasma-negative group in terms of sperm characteristics. Sperm motility and sperm vitality in the Mycoplasma-positive group were much lower than those in the Mycoplasma-negative group (p = 0.02 and p < 0.001, respectively). Conclusion: The presence of U. urealyticum in the semen of infertile men did not affect the sperm characteristics. Although the positive rate of M. genitalium was low, colonization by these bacteria was more likely to negatively affect sperm quality. Key words: Ureaplasma urealyticum, Mycoplasma genitalium, Infertility, Spermatozoa

A survey of multi-access edge computing in 5G and beyond : fundamentals, technology integration, and state-of-the-art

Driven by the emergence of new compute-intensive applications and the vision of the Internet of Things (IoT), it is foreseen that the emerging 5G network will face an unprecedented increase in traffic volume and computation demands. However, end users mostly have limited storage capacities and finite processing capabilities, thus how to run compute-intensive applications on resource-constrained users has recently become a natural concern. Mobile edge computing (MEC), a key technology in the emerging fifth generation (5G) network, can optimize mobile resources by hosting compute-intensive applications, process large data before sending to the cloud, provide the cloud-computing capabilities within the radio access network (RAN) in close proximity to mobile users, and offer context-aware services with the help of RAN information. Therefore, MEC enables a wide variety of applications, where the real-time response is strictly required, e.g., driverless vehicles, augmented reality, robotics, and immerse media. Indeed, the paradigm shift from 4G to 5G could become a reality with the advent of new technological concepts. The successful realization of MEC in the 5G network is still in its infancy and demands for constant efforts from both academic and industry communities. In this survey, we first provide a holistic overview of MEC technology and its potential use cases and applications. Then, we outline up-to-date researches on the integration of MEC with the new technologies that will be deployed in 5G and beyond. We also summarize testbeds and experimental evaluations, and open source activities, for edge computing. We further summarize lessons learned from state-of-the-art research works as well as discuss challenges and potential future directions for MEC research