MACRO-ZOOPLANKTON ABUNDANCE IN RELATION TO METAL ACCUMULATION AND WATER QUALITY IN TRUC BACH LAKE

Urban lake pollution is one of the serious issues due to suffering of waste discharged from householders. However, there is a gap of knowledge about the diversity of zooplankton species and how metals accumulate in zooplankton in urban ecosystems. We addressed this by determining the rule of blooming macro-zooplankton in Truc Bach lake and levels of two essential metals: copper (Cu), and zinc (Zn) and of three non-essential metals: arsenic (As), and lead (Pb) in water samples were determined. The results showed that Cladocerans and copepods are macro-zooplankton dominant species in Truc Bach Lake. Water temperature significantly affects the variety of copepod blooming. Arsenic concentration in water collected from the lake exceeded the safety level of current Vietnamese regulation. As concentration in macro-zooplankton positively correlated with metal concentrations in the water (p 0.05) while the concentration of Cu, Zn, and Pb in water has no significant correlation with the metal in zooplankton’s body. The relative abundance of adult copepods in Truc Bach lake had a negative correlation with As concentration in water (p = 0.01). The higher As concentration in water, the lower relative abundance of copepods was found in the sample

Production of gamma-aminobutyric acid by lactic acid bacteria of marine origin from Vietnam

Gamma-aminobutyric acid (GABA) is a non-proteinogenic amino acid, which functions as a neurotransmitter in the central nervous system. GABA has been shown to have several positive effects on human health, including reducing anxiety and promoting relaxation. In this study, various fermented fish products were screened for their ability to produce GABA. A total of 35 acid lactic producing strains were isolated from 8 samples of marine organism, 10 strains were found to have GABA-producing abilities. These strains were identified using 16S rDNA sequencing. The GABA concentrations produced by the 10 isolates ranged from 725 to 5590 mg/L. Lactobacillus brevis GB111 is the best isolated GABA producing strain, with a conversion rate up to 90.3%, which suggests that these strains may have potential applications in the food and pharmaceutical industries as a source of GABA

Effects of palladium on the optical and hydrogen sensing characteristics of Pd-doped ZnO nanoparticles

Abstract The effect of palladium doping of zinc oxide nanoparticles on the photoluminescence (PL) properties and hydrogen sensing characteristics of gas sensors is investigated. The PL intensity shows that the carrier dynamics coincides with the buildup of the Pd-related green emission. The comparison between the deep level emission and the gas sensing response characteristics allows us to suggest that the dissociation of hydrogen takes place at Pd Zn -vacancies ([Pd 2+ (4d 9 )]). The design of this sensor allows for a continuous monitoring in the range of 0-100% LEL H 2 concentration with high sensitivity and selectivity. 126

Using metagenomics tool to evaluate the enrichment efficiency of methanogens in marine sediment in Truong Sa archipelage, Khanh Hoa province, Vietnam

Methanogens (archaea bacteria that produce methan) play an important role in the anaerobic digestion of organic waste, however, in marine environment, the low density of methanogens makes anaerobic digestion very slow. In this study, we used methagenomics tool to evaluate the enrichment efficiency of methanogens communities in marine sediments as a basis for building a anaerobic microbial formulation to treat organic waste in marine environment. The results of determination of methanogen density by MPN method have shown that methanogen has been accumulated with higher density (up to 3.2.107 MNP/ml) through 2 times of enrichment in artificial seawater with CH3COONa 10 mM substrate. In addition, metagenomics data have also shown a decrease in the number of archaea species through each enrichment, indicating that methanogenic species have gradually dominated the microbial community. This is the first study on using metagnenomics tools to evaluate the enrichment of methanogens in marine sediment samples in Truong Sa archipelago, Vietnam. Metagenomics data help provide more reliable evidence in microbial studies, especially in obligate anaerobes such as methanogens

Exploiting secure performance of full-duplex decode and forward in optimal relay selection networks

In the presence of an illegitimate user, we investigate the secrecy outage probability (SOP) of the optimal relay selection (ORS) networks by applying decode-and-forward (DnF) based full-duplex (FD) relaying mode. The closed-form expressions for the allocations of the end-to-end signal-to-interference-plus-noise ratio (SINR) in each wireless network are derived as well as the closed-form expression for the exact SOP of the proposed ORS system is presented under Rayleigh fading schemes. As an important achievement, SOP is also compared between orthogonal multiple access (OMA) and non-orthogonal multiple access (NOMA) schemes. Our results reveal that the SOP of the suggested scheme can be considerably influenced by several parameters involved, including the number of relays, the average signal-to-noise ratio (SNR) of eavesdropper links, transmit power and the average residual self-interference (SI) enforced on the FD relays.Web of Science244767

Facile Synthesis of Carbon Quantum Dots by Plasma-liquid Interaction Method

Carbon quantum dots (CQDs) are a novel type of fluorescent nano-materials with various unique properties. They are recently attracting enormous interest due to their superiority in water solubility, chemical inertness, low toxicity, ease of functionalization as well as resistance to photo-bleaching and potential applications in biomedical indication, photo-catalysis, energy conversion, optoelectronics, and sensing. In this work, we present a facile and environmentally friendly synthesis of CQDs based on plasma - liquid interaction method. This is a single-step method and does not use toxic chemicals. The size distribution of obtained CQDs is rather uniform at approximately 3 nm. The emission peak of CQDs shifts from 427 nm to 523 nm as the excitation wavelength is varied from 340 nm to 460 nm. The non-equilibrium reactive chemistry of plasma liquid interaction is responsible for acceleration of the CQDs formation process

Multifunctional nanocarriers of Fe3O4@PLA-PEG/curcumin for MRI, magnetic hyperthermia and drug delivery

Background: Despite medicinal advances, cancer is still a big problem requiring better diagnostic and treatment tools. Magnetic nanoparticle (MNP)-based nanosystems for multiple-purpose applications were developed for these unmet needs. Methods: This study fabricated novel trifunctional MNPs of Fe3O4@PLA-PEG for drug release, MRI and magnetic fluid hyperthermia. Result: The MNPs provided a significant loading of curcumin (∼11%) with controllable release ability, a high specific absorption rate of 82.2 W/g and significantly increased transverse relaxivity (r2 = 364.75 mM-1 s-1). The in vivo study confirmed that the MNPs enhanced MRI contrast in tumor observation and low-field magnetic fluid hyperthermia could effectively reduce the tumor size in mice bearing sarcoma 180. Conclusion: The nanocarrier has potential for drug release, cancer treatment monitoring and therapy.The authors are grateful for the financial support by AOARD under award FA2386-17-1-4042. The Spanish government is acknowledged for the “Nanotechnology in translational hyperthermia (HIPERNANO)” research network (RED2018102626-T) and for funding under the project number MAT2017-83631-C3. NTK Thanh thanks EPSRC (EP/M015157/1). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed

Antioxidant and in vitro antidiabetic activities of Peperomia pellucida (L.) Kunth extract

Peperomia pellucida (L.) is commonly used as a herbal plant. Its effectiveness in treating inflammatory diseases, digestive disorders, and cancer in tropical and subtropical countries was introduced, especially in field of folk medicine. However, this plant species has not been studied widely in Vietnam, especially for its biological activities. This study was done to determine the antioxidant capacity of P. pellucida by using in vitro and in vivo methods, as well as its inhibitory ability to α-amylase enzyme activity. The total polyphenolic and flavonoid contents of P. pellucida extract were reported to be 359.91±0.77 mg GAE/g and 200.28±1.23 mg QE/g extract, respectively. The results showed the in vitro antioxidant activity of P. pellucida extract in four methods, including DPPH, and ABTS.+, RP and TAC, had EC50 values of 730.34 μg/mL, 84.33 μg/mL, 95.28 μg/mL, respectively, and Abs0.5 value of 114.73 μg/mL. Under H2O2-induced oxidative stress, fruit flies that were raised in the feed medium supplemented with a concentration of 1 mg/mL of P. pellucida extract showed their average survival time, 50% survival time, and 10% survival time at 1.6 times, 1.8 times, and 1.62 times, respectively, higher than those of the control treatment. The ability to inhibit the α-amylase activity in P. pellucida extract was determined with an EC50 value of 115.32±2.65 μg/mL compared with the commercial drug of 18.67±0, 01 μg/mL. The research results showed that P. pellucida is a potential species in the study of natural compounds with antioxidant and antidiabetic activities

ĐẶC ĐIỂM SINH HỌC SINH SẢN CỦA NGÁN (AUSTRIELLA CORRUGATA) TẠI VÙNG TRIỀU VEN BIỂN TỈNH QUẢNG NINH

360 samples of mud clam (Austriella corrugata) were collected in the intertidal zone of Quang Ninh province city from January 2015 to December 2015 for this study. The results showed that the gonad of female is black, that of male is milky white. The spawning season is from mid April to early September and the peak of spawning occurs from early June to early August. In spawning season, ratio of male/female is toward balance. In other months, rate of male is dominant in the population. Hermaphroditism occurs in the mud clam with a small percentage (from 3.3% to 10%) in the breeding season, in group with size of more than 40 mm. The length of mud clam at first sexual maturity is over 30 mm and the weight is over 20 g. The average absolute fecundity (Fa) is 960,680 eggs/individual. Development of mud clam larvae goes through main stages: Veliger, Umbo and Spat. Our findings contribute information to the planning of the artificial seed production, conservation and sustainable development of mud clam native resource.Kết quả phân tích 360 mẫu ngán (A. corrugata) thu tại các khu vực nơi có ngán phân bố thuộc vùng triều ven biển tỉnh Quảng Ninh từ tháng 1/2015 đến tháng 12/2015 cho thấy: Tuyến sinh dục ngán đực có màu trắng sữa, ngán cái có màu đen thẫm. Mùa vụ sinh sản của ngán hàng năm được xác định từ giữa tháng 4 đến đầu tháng 9, mùa sinh sản tập trung từ đầu tháng 6 đến đầu tháng 8. Ở các tháng tromg năm, tỷ lệ con đực luôn chiếm ưu thế so với con cái trong quần đàn ngán. Vào mùa sinh sản tỷ lệ đực cái cân bằng. Ngán lưỡng tính xuất hiện với tỷ lệ nhỏ (3,3 - 10%) vào mùa sinh sản và ở nhóm kích thước lớn hơn 40 mm. Ngán thành thục sinh dục lần đầu khi chiều dài đạt trên 30 mm, khối lượng trên 20 g. Sức sinh sản tuyệt đối giao động từ 340.690  - 2.090.000 trứng/cá thể, trung bình đạt 960.680 trứng/cá thể. Ấu trùng của ngán phát triển trải qua các giai đoạn chính: Ấu trùng chữ D, ấu trùng đỉnh vỏ và ấu trùng chân bò. Sau đó, ngán phát triển thành con non. Kết quả nghiên cứu góp phần cung cấp cơ sở khoa học cho việc xây dựng kế hoạch sản xuất giống nhân tạo, bảo vệ và phát triển bền vững nguồn lợi ngán tại địa phương