Natural sciences and Technology

Along with the development of science and technology and the application of the achievements of the 4th Industrial Revolution, many countries around the world have succeeded in building a smart city model that contributes to improving the quality of life, improving the service quality of the city government, reducing energy consumption, and enhancing the effective management of natural resources. This article aims to propose technological solutions in smart city management and development associated with digital transformation.

8p vibecca 01-10-2024 2 1   Download

The Free Water Surface wetland (FWS) has emerged as a promising technological solution for wastewater treatment in natural environments. The study aimed at investigating the performance of a laboratory-scale Free Water Surface wetland (FWS) unit designed to treat domestic wastewater with a daily capacity of 20 liters.

9p vibecca 01-10-2024 3 0   Download

Flavonoids are a diverse group of natural compounds extensively studied in various research articles. They are widely distributed in the plant kingdom and exhibit various biological activities, including antioxidant, antiinflammatory, anticancer, antiviral, and antimicrobial effects. The genus Knema Lour., which contains many species in Southeast Asia, has been traditionally used to treat various ailments. The current review aims to provide a comprehensive update on the isolation of flavonoids and other secondary metabolites from the genus Knema Lour. between 1978 and 2022.

15p dianmotminh02 03-05-2024 9 3   Download

The essential oils from the needles and branch of the Abies delaveyi subsp. fansipanensis was collected in Hoang Lien Natural Park, Lao Cai province and was obtained by steam distilation and the yields of essential oils were 0.27% and 0.08% from air-dry material. By the using GC/MS analysis, there are 44 and 52 constituents from needles and branch were identified and accounting 97.75% and 96.86% essential oil.

6p meyerowitz 25-12-2021 31 2   Download

The present study focused on isolation, identification, and evaluation of glass biodeterioration properties such as organic acid and exopolysaccharide production of fungal strain Chaetomium globosum TTHF1-3 isolated from lens of optical instrument collected at Thai Hoa, Nghe An province.

9p meyerowitz 25-12-2021 10 0   Download

In this study, the DNA fragment encoding for the C-terminus domain of the AopB from Aeromonas hydrophila AH-1 was cloned into pET-M expression vector and expressed in Escherichia coli BL21 (DE3) host cells. The recombinant AopB-C-terminus domain was successfully purified using immobilized nickel affinity chromatography as a soluble form. Crosslinking analysis among AopB-C-terminus molecules in solution showed that this domain existed as a mixture of tetramer, trimer, dimer, and monomer forms.

6p guitaracoustic02 08-12-2021 18 3   Download

In this study, we studied the effects of different environmental factors such as light, temperature and air humidity and of internal SBES factors such as sulfate concentration, dissolved oxygen concentration and biocathode on voltage reversal in the SBES.

9p guitaracoustic02 08-12-2021 17 3   Download

This study was carried out to evaluate the effect of Cobalt chloride (CoCl2) on cardiac mitochondrial function in an in vitro model. In the study, H9C2 cardiomyocytes were cultured in a medium containing different concentrations of CoCl2. Cell viability, cardiolipin content, mitochondrial function, and mitochondrial oxidative stress were assessed by using Cell Counting Kit-8 and suitable fluorescence kits.

6p guitaracoustic02 08-12-2021 5 2   Download

In this study, we investigated whether osteoporosis-like phenotype could be induced in the transgenic larvae when heat-shock was applied at earlier time points, namely when larvae were at 1,2,3,4,5, or 6 dpf. The obtained results show that heat-shocks from the time point of 3 dpf onwards resulted in osteoporosis-like phenotype, while heat-shock at 1 or 2 dpf did not affect mineralized bone matrix in 11 dpf larvae.

7p guitaracoustic02 08-12-2021 8 1   Download

The diversity of medicinal plants in Vietnam is a rich source to develop novel health products. In this study, the antioxidant and antimicrobial activities of ethanolic extracts of Pluchea indica, Drynaria fortunei, Stephania glabra, lemongrass (Cymbopogon citratus) and lime (Citrus aurantifolia) mixture, and ginger (Zingiber officinale) and kumquat (Citrus japonica) mixture, were evaluated.

7p guitaracoustic02 08-12-2021 13 1   Download

This paper presents a new record of the fern genus Arachniodes Blume from Vietnam, Arachniodes simplicior. The paper provides a detailed description of the new species based on the traditional morphological method, of which micro morphological characters of spores were firstly described based on the specimens collected from Quang Binh (Minh Hoa district), Vietnam. In addition, type materials of A. simplicior were analyzed and a specimen from MAK (MAK012702) was designated as a lectotype.

5p larachdumlanat129 14-01-2021 14 3   Download

This study aims to compile a detailed checklist of grammitid specimens kept in the Biological Museum Herbarium under VNU University of Science (HNU). The study adopted the Pteridophyte Phylogeny Group classification (PPG I 2016) to classify these specimens and fifteen references were used to identify their scientific names.

10p larachdumlanat129 14-01-2021 11 1   Download

Tổng hợp 170 bài mẫu Writing Task 2 theo chủ đề IELTS essay sample; education; the environment and natural source; science and technology; the media; advertisement and customer.

168p nguoiham 22-10-2020 147 26   Download

In Vietnam, the role of the tourism industry in the development of the country has been well recognized and has received early investment attention from the Party and the State. Quang Binh is a central province of Vietnam blessed with many natural beauty, historical sites, which is also a place attracting many tourists from all over the world.

7p tamynhan4 06-09-2020 18 1   Download

Natural precious products such as aroma compounds, essential oils, and bio-activated materials are usually extracted from about 30,000 botanical species. These extracts are often high competitive market due to their small content (less than 1 %) in plants and high purification cost. Thus, development of a modeling for the optimization of the crude oil extraction is highly paid attention. In this work, a modeling of Vietnam lemongrass oil extraction using steam distillation is developed and the optimization of the process parameters is performed using response surface methodology (RSM).

6p abcxyz123_02 03-03-2020 31 2   Download

“Linh chi” - the Vietnamese name for Ganoderma can be used in the prevention and treatment of various types of disease. Various compounds have been isolated from the fruiting bodies, spores, gills, and mycelia of many Ganoderma mushrooms. Ganoderma contains many bioactive natural components, including triterpenes, steroid, polysaccharides, proteins, and unsaturated fatty acids.

7p abcxyz123_02 03-03-2020 11 1   Download

This paper presents some results on the survey of the impact of silica and black carbide on the mechanical – physical properties and vibration resistance of the rubber blended on natural rubber (NR) and synthetic styrene butadiene rubber (SBR), for application in manufacturing diesel engine mounts.

7p abcxyz123_02 03-03-2020 16 1   Download

The present paper addresses the problem for free vibration of multistep Timoshenko beams with arbitrary number of cracks, continuing the work accomplished in [28], where the problem was studied on the base of Euller-Bernoulli beam theory. First, the obtained general solution of uniform Timoshenko beam is employed to develop the TMM for modal analysis of multistep Timoshenko beam with multiple cracks. Then, effect of beam slenderness and stepped change in cross section on sensitivity of natural frequencies to cracks is thoroughly examined.

16p abcxyz123_02 03-03-2020 20 3   Download

This is a paper supporting the demonstration of the LX-Center at ACL-IJCNLP-09. LX-Center is a web center of online linguistic services aimed at both demonstrating a range of language technology tools and at fostering the education, research and development in natural language science and technology.

4p hongphan_1 15-04-2013 60 3   Download

In this paper, we are dealing with a L-band power combiner method using the Wilkinson bridge. This is a modern power combination technique in the microwave technology. The design and simulink of the basic power moduls and Wilkinson bridge were performed using the ADS soflware. We have researched, designed and fabricated the power combination from the basic 200W moduls. The experimental results showed that power combination method using the Wilkinson bridge may be applicable in the L-band transmission....

5p tuanlocmuido 19-12-2012 74 3   Download