PRE-ENGINEERED (PACKAGE/AND OR ON-SITE) WASTEWATER TREATMENT PLANTS

Joint Research on Environmental Science and Technology for the Eart

Optimization of Weld Parameters in Wire and Arc-Based Directed Energy Deposition of High Strength Low Alloy Steels

This paper aims to investigate the fabrication of high strength low alloy (HSLA) steels by wire and arc-based directed energy deposition (WADED). Firstly, the relationship between the process variables (including the travel speed-V, the current-C, and the voltage-U) and the geometrical characteristics of weld beads (including the bead height (BH), bead width (BW), and melting pool length (MPL)) was investigated. Secondly, the optimal process variables were identified using the desirability approach. The results indicate that voltage-U has the highest impact on BW and MPL, meanwhile the travel speed-V is the most impacting factor on BH. The optimal variables for the WADED process of HSAL steels are V = 0.3 m/min, C = 160 A, and U = 19 V. The component fabricated with the optimal variables is fully dense without spatters and defects, confirming the efficiency of the WADED process for HSLA steels

Eupolauridine alkaloids of Polyalthia nemoralis

Two eupolauridine alkaloids, eupolauridine (1) and 8-methoxyeupolauridine (2), together with a phenanthrene compound, 2,7-dihydroxy-3,6-dimethoxyphenanthrene (3), were isolated from the ethyl acetate extract of Polyalthia nemoralis barks. Their structures were elucidated on the basis of spectroscopic analysis and comparison with related known compounds. These compounds were evaluated the cytotoxicity on seven human cancer cell lines including KB, MCF7, LU-1, HepG2, LNCap, SW626 and SW480

PILOT SCALE STUDY ON AMMONIUM REMOVAL IN PHAP VAN WATER PLANT, HANOI CITY

Joint Research on Environmental Science and Technology for the Eart

IDENTIFICATION AND ANTIMICROBIAL ACTIVITY OF ACTINOMYCETES STRAINS ISOLATED FROM SAMPLES COLLECTED IN THE COASTAL AREA OF HUE, DA NANG AND QUANG NAM PROVINCES, VIETNAM

Microorganisms are of particular interest because of their ability to synthesize high-value secondary compounds and provide us with novel and diverse chemical structures. The most common source of antibiotics is Actinomycetes which provide around two-third of naturally occurring antibiotics, including many of medical importance. In this study, 81 strains of actinomycetes were isolated from 145 samples including: sediments, sponges, soft corals, echinoderms and starfish collected from three sea areas of Vietnam: Hue, Da Nang and Quang Nam. The strains were fermented in A+ medium and fermentation broths were extracted 5 times with ethyl acetate. The extracts were evaporated under reduced  pressure to yield crude extracts. Quantitative assay was used to determine MIC (Minimum inhibitory concentration) of extract against 7 reference strains. From the results of screening, Seven strains of actinomycetes that have the highest biological activity (Code: G244, G246, G261, G266, G278, G280 and G290) were chosen to be identified by morphological and phylogenetic based on 16S rRNA gene sequences. The results showed that 6 strains G246, G261, G266, G278, G280 and G290 belonged to the genus Streptomyces; and the strain G244 belonged to the genus Micromonospora. In particular, strains G244, G278, G280 were resistant 5/7 strains of microorganisms test, with values  MICs from 2 µg/mL to 256 µg/mL; and three strains G261, G266, G290 showed the inhibitory effect towards 4/7 strains of microorganisms test, with respective values MICs from 2 µg/mL to 256 µg/mL. Moreover, six of the seven selected strains were highly resistant to yeast Candida albicans ATCC10231 with MIC values from 2 µg/mL to 256 µg/mL. These results indicated that marine Actinomycetes in Vietnam are also a potential source to find bioactive substances

In vitro growth and content of vincristine and vinblastine of Catharanthus roseus L. hairy roots in response to precursors and elicitors

Catharanthus roseus L. is a medicinal plant that produces numerous indole terpenoid alkaloids, including vincristine and vinblastine, which are used for cancer treatment. The effect of specified precursors (L-phenylalanine, L-tyrosine) and elicitors (chitosan, methyl jasmonate) on C. roseus hairy roots (CHR) growth has been examined in order to increase the content of vincristine and vinblastine. Our results showed that CHR generated by an Agrobacterium rhizogenes strain isolated in Vietnam was capable of producing both vincristine and vinblastine when subjected to precursors, but only vinblastine when exposed to elicitors. However, both precursors and elicitors were evaluated to have an effect on increasing the accumulation of TIAs in CHR. In particular, the use of elicitors required more time to find the appropriate induction conditions, while the use of precursors gave outstanding efficiency in the treatment with 1 µM phenylalanine. The greatest yields of vincristine (51.99 µg g-1 DW) and vinblastine (699.92 µg g-1 DW) were obtained in the 7th week (with 0.306 g DW biomass). This result is the first time we might boost the levels of vincristine and vinblastine in our CHR clone generated by the Vietnam strain of A. rhizogenes

Some preliminary results of paleo-tsunami study in the coastal region of the Nghe An province, Vietnam

In the coastal region of the Nghe An province, the geomorphology is characterized by appearances of fields of arca granosa with placura placenta and hills of placura placenta with arca granosa, namely: The hills of placura placenta with the arca granosa shells in the Quynh Van and Nghi Tien communes; the fields of arca granosa with the placura placenta: deep-seated in the Quynh Nghia, Dien Chau and along the Nghi Yen coast  which have age of 4,500 - 4,300 yrs.; The appearance of the placura placenta-arca granosa shell’s fields and hills which do not originate from either marine transgression in the Holocene epoch, tectonic movement or artificiality; Our results suggest that there were three tsunami events occurring in the past during the periods of 4,500 - 4,300; 4,100 - 3,900 and 900 - 600 yrs., respectively in the region

A practical synthesis of fluoroquinolone antibiotic moxifloxacin

The fluoroquinoloneantibiotic has been used in clinical practice since the 1980s, primarily for the treatment infections caused by Gram-negative bacteria. Moxifloxacin, a fourth-generation fluoroquinolone antibiotic developed by pharmaceutical company Bayer AG, exhibit broad spectrum of activity against Gram-negative, Gram-positive bacteria as well as  anaerobia. Moxifloxacin is used for community-acquired respiratory tract infections, sinusitis, acute exacerbations of chronic bronchitis and pneumonia, and skin structure infections. We have described the synthesis of moxifloxacin using difluoroboron complex. In this paper, a practical synthesis of moxifloxacin using acetoxyboronate complexwas reported

Lignans isolated from the ethyl acetate extract of Knema pachycarpa fruit

Knema is a genus of tropical evergreen trees of the family Myristicaceae found in South East Asian countries such as Vietnam, Thailand, and Malaysia. In this paper, four lignans, (+)-pinoresinol (1),(+) epi-pinoresinol (2), piperitol (3), and pluviatilol (4), were isolated from the ethyl acetate extract of the fruit of Knema pachycarpa, an indigenus tree in Vietnam. The chemical structures were determined by spectroscopic data and comparison with the reported literature. These compounds were isolated from Knema genus for the first time. Keywords. Knema pachycarpa de Wilde, (+)-Pinoresinol, (+)-Epi-pinoresinol, Piperitol, Pluviatilol