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Open access

Ngo Trung Thanh, Philippe Lebailly and Nguyen Thi Dien

Abstract

Many researchers have tried to explain the motivation behind out and return migration. However, few bodies of literature focus on selection of destinations of out migration, motives to return according to marriage status of migrants before the return and gender perspective of employments on the return. By surveying 68 returnees and applying participatory rural appraisal, this study shows that the personal and household characteristics of returnees before the migration create an effect on destination selections On the return, both single and married migrants are motivated by filial obligations to their parents. Single migrants’ motive associates to the potential failures that can be a burden on their livings after getting married. Married migrants’ motive to return results from living away from their children. This study also demonstrates that women play an important role in the development of agriculture. Additionaly, agriculture acts as a buffer to the negative impacts of return migration.

Open access

Ngo Thi Lu, Phung Thi Thu Hang, Nguyen Huu Tuyen, Ha Thi Giang and Nguyen Thanh Hai

Abstract

This article examines in detail the characteristics of Dien Bien earthquake on 19 February 2001 and its aftershocks. On the basis of the temporal development of aftershocks and the spatial distribution of tectonic faults, five aftershock series have been determined. The analysis of spatial distribution and temporal evolution of these five aftershock series has clarified the development in the source zone of Dien Bien earthquake, which is closely related to the active and recent activities of tectonic faults in the area, especially Lai Chau Dien Bien fault. The comparison between characteristics of aftershock activities of Dien Bien earthquake and geomorphological features as well as tectonic activities in the area has indicated that the magnitude of these aftershocks and their temporal evolution (early or late) depend not only on the closer or further distance compared to the mainshock and the active faults that cause them but also on terrain elevation, slope index, lineament density and their positions relative to other tectonic faults in the studied area.

Open access

Cao Ngoc Dan Thanh, Vo Thi Kim Quyen, Nguyen Thanh Tin and Bui Xuan Thanh

Abstract

There was an investigation into the removal of 6 types of antibiotics from hospital wastewater through membrane bioreactor (MBR) treatment and ozonation processes. Six types of antibiotics, namely, Sulfamethoxazole (SMZ), Norfloxacin (NOR), Ciprofloxacin (CIP), Ofloxacin (OFL), Erythromycin (ERY), and Vancomycin (VAN) which had high detection frequencies in collected samples from hospital wastewater treatment plant (HWTPs). After MBR treatment, the removal efficiencies of SMZ, NOR, OFL, and ERY were 45%, 25%, 30%, and 16%, respectively. Among of them, almost no elimination was observed for CIP and VAN since their concentrations increased by 0.24 ± 0.18 (μg·l-1) and 0.83 ± 0.20 (μg·l-1), respectively. Then, residues of the antibiotics were removed from the MBR effluent by the ozonation process. The overall removal efficiencies of SMZ, NOR, CIP, OFL, ERY, and VAN were approximately 66 %, 88 %, 83 %, 80 %, 93 %, and 92 %, respectively. The reason might be depended on different ozone consumption of those antibiotics (ABS) in a range of 313 to 1681 μg ABS·gO--1. Consequently, the ozonation process performed better in the antibiotics removal (e.g. CIP and VAN) so ozonation could be considered as important support for the MBR treatment to reduce the risk of antibiotic residues.

Open access

Nguyen Thi Thuy Trang, Le Thi Hoang Yen, Le Thi Hong Hanh and Bui Xuan Thanh

Abstract

Never human being has to face such a serious lack of phosphorus and pollutants from human activities. Nutrient recovery from wastewater is a new trend which attracts the interests of several researchers. Extraction of the nutrients, based on struvite crystal from wastewater as nutritious sources, has been assessed as an urgent solution to tackle the water pollution issue. This review focused on feature characteristics of struvite as a chemical fertilizer for plant, struvite formation process in various wastewaters, which is related to physio-chemical conditions, and potential of applying this idea into practice.

Open access

Nguyen Thi Thanh Huong, Pham Anh Duc and Pham Van Mien

Abstract

The pollution on the Thi Vai River has been spreading out rapidly over the two lasted decades caused by the wastewater from the industrial parks in the left bank of Thi Vai River and Cai Mep Estuaries. The evaluation of the benthic macroinvertebrate changes was very necessary to identify the consequences of the industrial wastewater on water quality and aquatic ecosystem of Thi Vai River and Cai Mep Estuaries. In this study, the variables of benthic macroinvertebrates and water quality were investigated in Thi Vai River and Cai Mep Estuaries, Southern Vietnam. The monitoring data of benthic macroinvertebrates and water quality parameters covered the period from 1989 to 2015 at 6 sampling sites in Thi Vai River and Cai Mep Estuaries. The basic water quality parameters were also tested including pH, dissolved oxygen (DO), total nitrogen, and total phosphorus. The biodiversity indices of benthic macroinvertebrates were applied for water quality assessment. The results showed that pH ranged from 6.4 – 7.6 during the monitoring. The DO concentrations were in between 0.20 - 6.70 mg/L. The concentrations of total nitrogen and total phosphorous ranged from 0.03 - 5.70 mg/L 0.024 - 1.380 mg/L respectively. Macroinvertebrate community in the study area consisted of 36 species of polychaeta, gastropoda, bivalvia, and crustacea, of which, species of polychaeta were dominant in species number. The benthic macroinvertebartes density ranged from 0 - 2.746 individuals/m−1 with the main dominant species of Neanthes caudata, Prionospio malmgreni, Paraprionospio pinnata, Trichochaeta carica, Maldane sarsi, Capitella capitata, Terebellides stroemi, Euditylia polymorpha, Grandidierella lignorum, Apseudes vietnamensis. The biodiversity index values during the monitoring characterized for aquatic environmental conditions of mesotrophic to polytrophic. Besides, species richness positively correlated with DO, total nitrogen, and total phosphorus. The results confirmed the advantage of using benthic macroinvertebrates and their indices for water quality assessment.

Open access

Dinh Thi Thanh Van and Nguyen Ha Linh

Abstract

Financial inclusion efforts seek to ensure that all members of an economy can have access to and effectively use appropriate financial services. Improving financial inclusion has become a significant concern for developed and developing countries alike. There are many indicators of financial inclusion, the most elementary of which includes having an account in a financial institution. This paper will evaluate the impact of indicators of financial inclusion on economic development. The result shows that correlations exist between large numbers of bank branches, ATMs, domestic credit in the private sector and the increased rate of development in the economy. People will gain a more prosperous life due to this development. The paper also provides recommendations for the governments of developing countries to improve financial inclusion.

Open access

Duong Thanh Tai, Luong Thi Oanh, Nguyen Dong Son and Truong Thi Hong Loan

Abstract

Introduction: Jaws-Only Intensity modulated radiation therapy (JO-IMRT) is a technique uses the collimator jaws of the linear accelerator (LINAC) to delivery of complex intensity patterns. In previous studies, pretreatment patient specific quality assurance for those JO-IMRT were also performed using ionization chamber, MapCHECK2, and Octavius 4D and good agreements were shown. The aim of this study is to further verify JO-IMRT plans in 2 different cases: one with the gantry angle set equal to beam angle as in the plans and the other with gantry angle set to zero degree.

Materials and Methods: Twenty-five JO-IMRT, previously verified, were executed twice for each plan. The first one used a real gantry angle, and the second one used a 0° gantry angle. Measurements were performed using Octavius 4D 1500.

Results: The results were analyzed using Verisoft software. The results show that the Gamma average was 97.32 ± 2.21% for IMRT with a 0° gantry angle and 94.72 ± 2.67% for IMRT with a true gantry angle.

Conclusion: In both cases, gamma index of more than 90% were found for all of our 25 JO-IMRT treatment plans.

Open access

Hieu Quang Tran, Hien Cao Nguyen, Thin Van Nguyen, Thanh Thi Nguyen, Toan Ngoc Vo and Cong Tien Nguyend

Abstract

Knoevenagel condensation of thiazolidine-2,4-dione, which were prepared from chloroacetic acid and thioure by 1,3 dipolar cycloaddition reaction, with 2-hydroxybenzaldehyde, 5-bromo-2-hydroxybenzaldehyde, 3-hydroxybenzaldehyde, 4-hydroxybenzaldehyde and 4-hydoxy-3-methoxybezaldehyde gave five corresponding 5-(hydroxybenzylidene)thiazolidine-2,4-dione compounds. The reaction of 5-(hydroxybenzylidene)thiazolidine-2,4-diones and ethyl chlorofomate or ethyl chloroacetate occurred at both NH and OH centers and gave ten corresponding diesters. The structures of the diesters were confirmed by IR, MS, 1H and 13C-NMR spectral data. However, in test for cytotoxic activity against MCF-7 cells, none of the diester compounds exhibited significant activity.

Open access

Pham Anh Duc, Nguyen Thi Mai Linh, Dang My Thanh and Pham Van Mien

Abstract

In this study, the variables of zooplankton and water quality were investigated in the Can Giuoc River, Southern Vietnam. Zooplankton was monitored in April and September 2015 at 5 sampling sites in the river. Some basic water quality parameters were also tested, including pH, total suspended solid (TSS), dissolved oxygen (DO), biological oxygen demand (BOD5), inorganic nitrogen (NH4 +), dissolved phosphorus (PO4 3−), and coliform. The zooplankton biodiversity indices were applied for the water quality assessment.

The results showed that pH ranged from 6.7 to 7.6 during the monitoring. The TSSs were between 34–117 mg/L. The DO and BOD5 were from 0.6 to 3.8 mg/L and from 6.3 to 13.2 mg/L, respectively. The NH4 + and PO4 3− concentrations ranged from 0.44 to 3.23 and from 0.08 to 1.85 mg/L, respectively. The coliform number was between 9.3×103–9.3×104 MPN/100 mL. The zooplankton analyses showed that there were 31 species of coelenterates, rotatoria, oligochaetes, cladocerans, copepods, ostracods, mysidacea, and 8 larval types. Thereof, the species of copepods were dominant in the species number. The zooplankton density ranged from 9 500 to 23 600 individuals/m3 with the main dominant species of Moina dubia (Cladocera), Thermocyclops hyalinus, Acartia clausi, Oithona similis (Copepoda), and nauplius copepods. The biodiversity index values during the monitoring were from 1.47 to 1.79 characteristic of mesotrophic conditions of the aquatic environment. Besides, the species richness positively correlated with pH, TSS, DO, BOD5, NH4 +, PO4 3−, and coliform, while the zooplankton densities got a positive correlation with DO, BOD5, NH4 +, PO4 3−, and coliform. The results confirmed the advantage of using zooplankton and its indices for water quality assessment.

Open access

Thanh Luan Nguyen, Jae Gyu Yoo, Neelesh Sharma, Sung Woo Kim, Yong Jun Kang, Hai Ha Pham Thi and Dong Kee Jeong

Abstract

Human, murine and monkey spermatogonial stem cells (SSCs) have the capability to undergo self-renewal and differentiation into different body cell types in vitro, which are expected to serve as a powerful tool and resource for the developmental biology and regenerative medicine. We have successfully isolated and characterized the chicken SSCs from 3-day-old chicken testicular cells. The pluripotency was using Periodic Acid-Schiff (PAS ) staining or alkaline phosphatase staining, and antibodies to stage-specific embryonic antigens. In suspension culture conditions SSCs formed embryoid bodies (EBs) like embryonic stem (ES) cells. Subsequently EB differentiated into osteoblasts, adipocytes and most importantly into cardiomyocytes under induced differentiation conditions. The differentiation potential of EBs into cardiomyocyte-like cells was confirmed by using antibodies against sarcomeric α-actinin, cardiac troponin T and connexin 43. Cardiomyocytes-like cells were also confirmed by RT-PCR analysis for several cardiac cell genes like GATA-4, Nkx2-5, α-MHC, and ANF. We have successfully established an in vitro differentiation system for chicken SSCs into different body cells such as osteoblasts, adipocytes and cardiomyocytes. The most significant finding of this study is the differentiation potential of chicken SSCs into cardiomyocytes. Our findings may have implication in developmental biology and regenerative medicine by using chicken as the most potential animal model.