118 research outputs found

    Sustainable Symbiotic Relationship in The Human Ecosystem in The Development of Public Spaces (Case of Hanoi Historical Inner-City Area)

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    In the last few years, the concept of the Human Ecosystem has been mentioned a lot frequently in Urban Environments related to social and natural ecosystems. The organization of public spaces cannot help but affect the relationships between human and natural ecology, economy, and culture. Perhaps the human activities have compromised the ecosystem so those relationships can be easily broken down. But it can also be enriched, or recovered from failures by establishing Symbiotic Relationships between natural, economic, and cultural elements in urban ecosystems. The research presents theoretical issues of Human Ecosystems in public space organization and specific applications in the case of Hanoi historical inner-city areas. It focuses on discussing theories of the structure and morphology of Human Ecosystems, the human behavior, the relationship between community behaviors, natural environment, and architecture of public spaces, to organize, enrich, and balance the service ecosystem of public spaces. These features are considered vital by the author in contributing to the preservation of natural resources, urban architectural heritage, creating architectural spaces and planning of public spaces towards ecological and green urban development

    Towards Developing the Smart Cultural Heritage Management of the French Colonial Villas in Hanoi, Vietnam

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    Hanoi city was formed and inherited a unique urban heritage. Among them are the French-colonial Villas, which were constructed in the pre–1954 period. During the development process, the local government and community have always paid special attention to these heritage sites and organized many conservation and research activities. However, the management and preservation of these sites are still facing many challenges under pressure from urbanization, environmental impact, leading to the risk of being invaded and destroyed. The objective of this paper is to discuss the potential of developing the management strategy for French colonial villas in Hanoi within contemporary society using the concept of the Smart Cultural Heritage. The authors believe that will support various cultural services as well as promoting and preserving cultural heritage. It does so by presenting the results of the survey of the status of villas in the French period in Hanoi to classify and evaluate establish the regulation of use management and value conservation, build up the Big Data system. At the same time, the proposal will use smart platforms and participatory processes to encourage community access to raise awareness and assess the villas' value

    Research on Factors Affecting Credit Risk of Joint Stock Commercial Banks on Vietnam Stock Market

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    Design/methodology/approach: The article aims at identifying factors affecting credit risk of commercial banks in Vietnam. The study uses data collected from financial statements of 15 typical joint stock commercial banks out of a total of 27 joint stock commercial banks listed on the Vietnam stock exchange from 2012 to 2022 with panel data of 15 joint stock commercial banks for the period 2012 - 2022. The banks in the research data are the those with the largest total assets in the banking system. After collecting and processing data, research sample includes 165 observations and the study uses E-view software in quantitative analysis to build a regression model to determine the relationship and level of influence of Internal factors to credit risk of listed joint stock commercial banks.   Findings: Research results indicate that factors affecting credit risk of listed joint stock commercial banks include: Ratio of equity to total assets, capital structure of the bank, and operational performance of the banks.   Research, Practical & Social impications: These results confirm the importance of taking into account micro finance factors when making financing. Understanding the impact of these factors and relationships contributes to decision and risk management.   Originality/value: In order to limit credit risk it is necessary to focus on: Ensuring reasonable equity; Stricter control over loan capital; Optimal use of resources

    Uptake capacity of metals (Al, Cu, Pb, Sn, Zn) by Vetiveria Zizanioides in contaminated water in the Dong Xam metal production trade village, Thai Binh, Vietnam

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    This study presents an experiment of metal contaminated water treatment under controlled environment conditions to investigate the uptake capacity of metals by Vetiveria Zizanioides to treat contaminated water from a metal production trade village, Dong Xam, Thai Binh, Vietnam. Vetiver was grown in two pot culture experiments TB10, TB6 with solutions containing respective concentrations of Al, Cu, Pb, Sn and Zn of 2.5, 55.6, 0.15, 7.7 and 24.4 mg from contaminated water in the Dong Xam metal production trade village for a period of 36 days. Vetiver has the higher tolerance to Al, Cu, Pb, Sn and Zn than other plant species. The roots (hereafter R) are high Al hyperaccumulators, concentrating 17 up to 30 folds more than “reference plant”. The upper parts of shoots (hereafter S1, S2, and S3) are 1.2 folds higher. Cu concentration in the root and shoot is up to 660 and 46.2 mg/kg, respectively. Vetiver can withstand and survive at Cu concentration of 46 mg/L in contaminated water that is markedly higher than other plants that can last only in solution with Cu concentration ranging 20-100 mg/kg. The translocation of Pb from root to shoot was 41%. Sn is more accumulated in the top, in which shoot/root ratio varied from 82% to 277% in the top, and increased to the top (by order S3/RS2/RS1/R). Zn could be translocated from roots and accumulated in shoots of vetiver. The ratio shoot/root obtains up to 46%. The present results demonstrated that vetiver had the high tolerance to trace metals Al, Cu, Pb, Sn and Zn in vegetation. This plant has a potential phytoremediation of metals in contaminated soil and wastewater from trade villages of Vietnam and other countries.References Adriano D.C., 1992. Biochemistry of trace metals. Lewis Publishers. Boca Raton, New York. 513 pp. Baker D.E., 1976. Acid soils. In Proc. of Workshop on Plant Adaptation to Mineral Stress in Problem Soils. Wright J. Ed. Cornell University. Ithaca. No4, 127. Becker H., 1992. Hedging against erosion. Agric. Res. 12, p.8-10. Braude G.L., Nash A.M., Wols W.J., 1980. Cadmium and lead content of soybean products. J. Food Sci., 45, 1187. Broyer T.C., Johnson C.N. and Paull R.E., 1972. Some aspects of lead in plant nutrition. Plant Soil. V36, p.301. Chiu K.K., Ye Z.H., Wong M.H., 2005. Enhanced uptake of As, Zn, and Cu by Vetiveria zizanioides and Zea mays using chelating agents. Chemosphere, 60, p.1365-1375. Chiu K.K., Ye Z.H., Wong M.H., 2006. Growth of Vetiveria zizanioides and Phragmities australis on Pb/Zn and Cu mine tailings amended with manure compost and sewage sludge: A greenhouse study. Bioresource Technology, 97, p.158-170. Cull, R.H., Hunter, H., Hunter, M., and Truong, P.N.,  2000.  Application of Vetiver Grass Technology in off-site pollution control.  II.  Tolerance of Vetiver grass towards high levels of herbicides under wetland conditions.  Proceedings of the Second International Vetiver Conference, Phetchaburi, Thailand, January 2000. Dabin P., Marafante E. et al., 1978. Adsorption, distribution and binding of cadmium and zinc in irrigated rice plants. Plant soil, 50, p. 329. Foy C.D., Chaney R.L. and White M.C., 1978. The physiology of metal toxicity in plants. Annu. Rev. Physiol. 29, p.511. Frank R., Stonefield K.I. and Suda P. 1979. Metals in agricultural soils of Ontario. Can. J. Soil Sci., 59, p.99. Grimshaw R G., 1989. A review of existing soil conservation technologies, and a proposed method of soil conservation using contour farming practices backed by vetiver grass hedge barriers. In Proc. vetiver Grass Seminar at the Int. Agric. Centre in Wageningen, The Netherlands, January, 1989. Hung-Yu Lai, Zueng-Sang Chen, 2004. Effects of EDTA on solubility of cadmium, zinc, and lead and their uptake by rainbow pink and vetiver grass. Chemosphere, 55, p.421- 430. Jensen K., Stephenson G., Hunt, L., 1977. Detoxification of atrazine in three Gramineae subfamilies. Weed Sci. 25, p.212-220. Kabata-Pendias Alina and Pendias Henryk, 2001. Trace elements in soils and plants. 3rd ed. CRC Press, Inc. Boca Raton, Florida, 413pp. Leckie J. O. and Davis J. A., 1979. Aqueous environmental chemistry of copper. In Copper in Environment (ed. J. O. Nriagu). Wiley, New York, pp.90-121. Markert B., 1992. Establishing of “reference plant” for inorganic characterization of different plant species by chemical fingerprinting. Water, Air, and Soil Pollution, 64: p.533-538. Mejare M., Bulow L., 2001. Metal-binding proteins and peptides in bioremediation and phytoremediation of heavy metals. Trends in Biotechnology, 19, p.67-73. Mickovski S.B., Beek L.P.H van and Salin F., 2005. Uprooting of vetiver uprooting resistance of vetiver grass (Vetiveria zizanioides). Plant and Soil, 278, p.33-41. Rommey E.M., Wallace A., and Alexander G.V., 1975. response of bush bean and barley to tin applied to soil and to solution culture. Plant Soil, 42, p.585. Sanita di Toppi L, Gabbrielli R. 1999. Response to cadmium in higher plants. Environ Exp Bot; 41:p.105-130. Schlesinger W. H. 2004. Treatise on geochemistry. Volume 8 Biogeochemistry. Executive editors H. D. Holland and K. K. Turekian. First edition 2004. Elsevier-Pergamon, Oxford. Steven T. S., Paul R. A., Ricarda N. K., 1999. Aquaculture sludge removal and stabilization within created wetlands. Aquacult. Eng. 19, p.81-92. Sylvie M., Muriel R., Patrick R., Jean-Paul S., 2006. Conjugation of atrazine in vetiver (Chrysopogon zizanioides Nash) grown in hydroponics. Environmental and Exp. Botany, 56, p.205-215. Tordoff G.M., Baker, A.J.M., Willis, A.J., 2000. Current approaches to the revegetation and reclamation of metalliferous mine wastes. Chemosphere, 41, p.219-228. Truong P. and Loch R., 2004. Vetiver System for erosion and sediment control. In Proc. 13th International Soil Conservation Organisation Conference, Brisbane, Australia, July 2004. pp.1-6. Truong P.N., 1996. Vetiver grass for land rehabilitation. In: Proceedings of the First International Vetiver Conferences, Thailand, pp.49-56. Truong P.N. and Baker D., 1998. Vetiver Grass System for Environmental Protection. Technical Bulletin N0. 1998/1.  Pacific Rim Vetiver Network, Office of the Royal Development Projects Board, Bangkok, Thailand. Truong P.N. and Hart B., 2001.  Vetiver System for Wastewater Treatment. Technical Bulletin NO. 2001/2.  Pacific Rim Vetiver Network, Office of the Royal Development Projects Board, Bangkok, Thailand. Veldkamp J. F., 1999. A revision of Chrysopogon Trin., including Vetiveria Bory (Poaceae) in Thailand and Malesia with notes on some other species from Africa and Australia. Austrobaileya 5: p.522-523. Wilde E.W., Brigmon R.L., Dunn D.L., Heitkamp M.A., Dagnan D.C., 2005. Phytoextraction of lead from firing range soil by Vetiver grass. Chemosphere, 61, p.1451-1457. World Bank, 1990. Vetiver Grass - The Hedge Against Erosion, 3rd ed. Washington D.C. Xia H.P., 2004. Ecological rehabilitation and phytoremediation with four grasses in oil shale mined land. Chemosphere, 54, p.345-353. Yahua C., Zhenguo S., Xiangdong L., 2004. The use of vetiver grass (Vetiveria zizanioides) in the phytoremediation of soils contaminated with heavy metals. Applied Geochemistry, 19, p.1553-1565. Yang B., Shu W.S., Ye Z.H., Lan C.Y., Wong M.H., 2003. Growth and metal accumulation in vetiver and two Sesbania species on lead/zinc mine tailings. Chemosphere, 52, p.1593-1600. Zhang J., 1998. Benefit and application future of sandy soils on windy Pingtan island. In: Vetiver Research and Development. Agricultural Science and Technology Press, China, pp.179-191. Zimdahl R.L., 1975. Entry and movement in vegetation of lead derived from air and soil sources. Paper presented at 68th Annu. Meeting of the Air Pollution Control Association, Boston, Mass., June 15, 1975, 2.

    Perspective Chapter: Uptake Capacity of Metals (Al, Cu, Pb, Sn, Zn) in Contaminated Water Metal Production Trade Village Dong Xam, Thai Binh, Vietnam by <em>Vetiveria zizanioides</em>

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    This chapter describes experiments, carried out under controlled environment conditions to investigate the uptake capacity of metals (Al, Cu, Pb, Sn, and Zn) by Vetiveria zizanioides to treat contaminated water from “metal production trade village Dong Xam, Thai Binh, Vietnam.” The roots have a high hyperaccumulation capacity of Al, and it is much more than “reference plant” about 17- up to 30-folds, and the upper parts of shoots S2, and S3 are higher 1.2-fold. In vetiver plant the Cu concentration can be obtained up to 660 mg/kg in root, and 46.2 mg/kg in shoot, and it can withstand and be alive at 46 mg/L of contaminated solution. The lead translocation from root to shoot reached to about 41%. The tin is absorbed in the leaf chop with ratio: Root varied from 82% up to ∼277% in the leaf chop. The zinc may be moved from roots and accumulated by the shoots of vetiver. The ratio shoot: root gets up to 46%. The study shows that vetiver had the high tolerance to trace metals Al, Cu, Pb, Sn, and Zn than other species plants. This plant has potential for usage in the phytoremediation of metals contaminated soil and wastewater from trade villages of Vietnam and other countries

    OPTICAL BISTABILITY IN A DEGENERATE TWO-LEVEL EIT MEDIUM UNDER THE INFLUENCE OF AN EXTERNAL MAGNETIC FIELD: AN ANALYTICAL APPROACH

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    We investigate the behavior of optical bistability in a degenerate two-level atomic medium using an external magnetic field to separate the lower level into two distinct levels that both connect to an upper level by the probe and coupling laser fields. Based on analytical solutions, the absorption spectrum and behavior of optical bistability in an electromagnetically induced transparency regime under an external magnetic field are investigated. By controlling the external magnetic field, we find that the appearance and disappearance of the optical bistability can be easily controlled according to the strength of the magnetic field in the transparent window domain. Furthermore, the effects of the intensity of the coupling laser field and the parameters of the system on the behavior of optical bistability are also considered. The proposed model is useful for applications in all-optical switches and magneto-optic storage devices.We investigate the behavior of optical bistability in a degenerate two-level atomic medium using an external magnetic field to separate the lower level into two distinct levels that both connect to an upper level by the probe and coupling laser fields. Based on analytical solutions, the absorption spectrum and behavior of optical bistability in an electromagnetically induced transparency regime under an external magnetic field are investigated. By controlling the external magnetic field, we find that the appearance and disappearance of the optical bistability can be easily controlled according to the strength of the magnetic field in the transparent window domain. Furthermore, the effects of the intensity of the coupling laser field and the parameters of the system on the behavior of optical bistability are also considered. The proposed model is useful for applications in all-optical switches and magneto-optic storage devices

    Isolation, screening antimicrobial activity and identification of fungi from marine sediments of the area Thanh Lan, Co To, Vietnam

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    Marine environment is rich in natural product resources, including marine microorganisms, especially fungi which are not only seen as a potential source of highly applicable bioactive substances but also can provide for science new chemical structures. The objective of this study is to isolate and screen fungal strains with antibacterial activity from the marine environment. Twenty five strains of fungi were isolated from marine sediments of Thanh Lan, Co To island and assessed on antibiotic activity against 7 tested microbial strains, including three Gram-negative bacteria (Escherichia coli ATCC25922, Pseudomonas aeruginosa ATCC27853, Salmonella enterica ATCC13076), three Gram-positive bacteria (Enterococcus faecalis ATCC29212, Stapphylococus aureus ATCC25923, Bacillus cereus ATCC 13245), and the yeast Candida albicans ATCC10231. The minimum inhibitory concentration (MIC) against the tested microorganisms was determined for the crude extracts obtained from the culture broths after ethyl acetate extraction and vacuum rotary evaporation. Three strains with the highest antimicrobial activity M26, M30 and M45 were capable of inhibiting 4 - 5 of the 7 tested microorganisms with MIC values from 64 to 256 μg/ml, depending on each tested strain. Morphological and phylogenetic investigations based on 18S rRNA gene sequences of the three selected strains showed that strains M26 and M30 belonged to the genus Penicillium, whereas strain M45 belonged to the genus Neurospora. The sequences of 18S rRNA gene of three strains M26, M30 and M45 were registered on GenBank database with accession numbers: MH673730, MH673731, MH673732, respectively. Research results showed that marine environment has a great potential in isolation of fungal strains for the search for antibacterial substances as well as other biologically active compounds

    Quantification of Three Dimensional Characteristics of Macrofauna Macropores and Their Effects on Soil Hydraulic Conductivity in Northern Vietnam

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    Soil bioturbation is associated with the production of soil macropores that influence numerous ecological functions such as those associated with water infiltration and the generation of runoff water. This impact is especially important on sloping lands in the tropics that are highly susceptible to erosion. In this study, we questioned the influence of soil biodiversity on soil macropore properties (&gt;20 mm3) and saturated hydraulic conductivity (Ksat) on sloping land in northern Vietnam. Biostructures found at the soil surface (casts, sheetings, and soil excavated on the ground) were used to identify areas colonized either by earthworms, termites or dung beetles, respectively. The influence of soil macrofauna on Ksat was measured in situ using the Beerkan method below bioturbated zones and compared to the surrounding soil without visible biostructures at the soil surface. Undisturbed soil columns were afterwards sampled and scanned by X-ray computed tomography (X-ray CT). Properties of macropores below each biostructure depicted a large variability, revealing the complexity of the macropore network. Further, galleries made by termites, dung beetles, and earthworms were manually isolated from the rest of macroporosity. Galleries made by beetles, termites and earthworms were clearly differentiated on the basis of their diameter, verticality, sphericity, tortuosity, length and number of branches and the fraction of galleries in the top part of the column. Ksat was most increased by dung beetles (45-fold), then by termites (30-fold) and to a lesser extent by earthworms (16-fold). Relationships between total macropore properties and Ksat showed that the most important properties explaining Ksat were (i) the volume of percolating macropores, (ii) the diameter, (iii) the critical macropore diameter, and (iv) the number of macropores. In conclusion, this study confirmed not only the interest in using X-ray CT for the quantification of macroporosity but also the absence of a clear relationship between aboveground biostructures and macropore properties and functional impacts

    Enzimatska obrada iskorištenih listića zelenog čaja i njihova primjena u proizvodnji čajnog peciva s velikim udjelom prehrambenih vlakana

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    Research background. By-products of food industry have been studied as sources of high fibre and antioxidant ingredients for healthy food products, because of their economic and environmental benefits. However, the soluble dietary fibre content of these materials is usually lower than the recommended value that is claimed to bring positive health effects. Enzymatic treatment could be an efficient method for modifying insoluble and soluble dietary fibre contents of these materials. The purpose of this study is to investigate the effects of enzymatic treatment conditions on soluble, insoluble and total dietary fibre mass fractions in spent green tea leaves, and evaluate the quality of dough and cookies when different mass fractions of untreated and treated leaves were added to the recipe. Experimental approach. The mass fractions of soluble, insoluble and total dietary fibre in spent tea leaf powder was evaluated after the leaves were treated with cellulase amount of 0−25 U/g for 0 to 2 h. Wheat flour was replaced by untreated and treated spent tea leaf powder at 0, 10, 20, 30 and 40% in cookie formulation. Textural properties of dough, proximate composition, physical properties and overall acceptability of cookies were analysed. Results and conclusions. The appropriate conditions for enzymatic treatment were enzyme loading of 20 U/g and biocatalytic time of 1.5 h, under which the mass fraction of soluble dietary fibre in spent tea leaves increased by 144.5% compared to that of the control sample. The addition of spent tea leaves led to the increase in dough hardness. Increase in the spent tea leaf amount also enhanced fibre mass fraction, antioxidant activity and hardness of cookies but reduced their overall acceptability. Moreover, the enzymatic treatment of spent tea leaves improved the soluble to total dietary fibre ratio of the cookies, which influenced their textural properties and health benefits. The cookies with added 20% untreated or treated spent tea leaves were overall accepted by the panel. Novelty and scientific contribution. For the first time, spent tea leaves have been treated with enzymes to improve their soluble to total dietary fibre ratio. The treated spent tea leaves are a new promising high-fibre antioxidant ingredient for cookie preparation.Pozadina istraživanja. Nusproizvodi prehrambene industrije ispituju se iz ekonomskih i ekoloških razloga kao izvori sastojaka s velikim udjelom prehrambenih vlakana i antioksidacijskim učinkom koji se mogu upotrijebiti u proizvodnji zdrave hrane. Međutim, udjel topljivih prehrambenih vlakana u nusproizvodima je obično manji od preporučenih vrijednosti koje mogu imati pozitivan učinak na zdravlje. Enzimatska obrada bi mogla biti učinkovita metoda modificiranja netopljivih i topljivih prehrambenih vlakana iz otpada prehrambene industrije. Svrha je ovog rada bila ispitati utjecaj različitih uvjeta enzimatske obrade na masene udjele topljivih, netopljivih i ukupnih prehrambenih vlakana u iskorištenim listićima zelenog čaja, te procijeniti kakvoću tijesta i čajnog peciva s dodatkom različitih masenih udjela obrađenih i neobrađenih listića. Eksperimentalni pristup. Maseni udjeli topljivih, netopljivih i ukupnih prehrambenih vlakana u prahu od iskorištenih listića zelenog čaja mjereni su nakon njihove obrade s 0–25 U/g celulaze tijekom 0 do 2 h. U smjesi za čajno pecivo je pšenično brašno zamijenjeno s 0, 10, 20, 30 i 40 % obrađenog ili neobrađenog praha iskorištenih listića zelenog čaja. Ispitani su tekstura tijesta te kemijski sastav, fizikalna svojstva i ukupna prihvatljivost dobivenog čajnog peciva. Rezultati i zaključci. Pri povoljnim uvjetima enzimatske obrade, a to su 20 U/g enzima i vrijeme trajanja biokatalitičkog procesa od 1,5 sata, maseni udjel topljivih prehrambenih vlakana u iskorištenim listićima zelenog čaja porastao je za 144,5 % u usporedbi s kontrolnim uzorkom. Dodatkom iskorištenih listića zelenog čaja povećala se tvrdoća tijesta. Povećanjem količine listića čaja povećali su se i maseni udjel vlakana, antioksidacijska svojstva i tvrdoća čajnog peciva, ali se smanjila njihova prihvatljivost. Osim toga, enzimatskom se obradom iskorištenih listića zelenog čaja poboljšao omjer topljivih i ukupnih vlakana u čajnom pecivu, što je utjecalo na njegovu teksturu i pozitivan učinak na zdravlje. Panel ocjenjivača je okarakterizirao čajno pecivo s dodatkom 20 % obrađenih ili neobrađenih iskorištenih listića čaja kao prihvatljive. Novina i znanstveni doprinos. Prvi put je enzimatskom obradom iskorištenih listića zelenog čaja poboljšan njihov omjer topljivih i ukupnih prehrambenih vlakana. Obrađeni iskorišteni listići zelenog čaja novi su obećavajući sastojak s antioksidacijskim svojstvima koji se može upotrijebiti u pripremi čajnog peciva

    Targeting effect of folate on cancer cell through curcumin carrier nano-system

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    Folate receptor (FR) is well known for its overexpression on surface of various cancer cell lines, which is identical to normal tissue. Folic-based targeting drug delivery systems, therefore, are one of the most effective targeting carriers that effectively bind to FR up-regulated cancer cells. Curcumin was used both for labeling and chemotherapy. The materials were characterized and structurally confirmed by FT-IR spectra, fluorescent images and FE-SEM images. Bioassays were conducted on HeLa and HT29 cancer cell lines after 4 and 12 hours. Results show that folic acid significantly enhanced both targeting efficiency and internalization of curcumin to FR-expressing cancer cells
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