Effects of yeast extract and methyl jasmonate on the enhancement of solasodine biosynthesis in cell cultures of Solanum hainanense Hance

In this work, the effects of the elicitors methyl jasmonate (MeJA) and yeast extract (YE) on the growth and solasodine production of Solanum hainanense cells were investigated. The results showed that various concentrations of MeJA (50-250 µM) and YE (1-4 g/L) have different eliciting influences. The increase of solasodine content induced by the elicitation of 3 g/L of YE and 50 µM of MeJA at the beginning of cell culture was about 1.9- and 1.3-fold, respectively, as compared with that of the non-elicitated cells. In general, YE (biotic elicitor) was more effective in enhancing solasodine production than MeJA (abiotic elicitor)

Social Networks along the Migration Cycle between Vietnam and Korea: Opportunities or Obstacles for Temporary Labour Migrants?

This thesis offers a comprehensive analysis of social networks applied to the specific case of temporary contract migration in an intra-regional (here, Asian) context. Although intra-Asian labour migration has been of increasing scholarly concern, the majority of such studies have focused on the economic and political aspects of migration, often in relation to development, to the exclusion of social networks for migrant workers. Given the significant impact of networks on the success of temporary migration for the individual migrants and their families, this thesis addresses important gaps in the study of international labour migration as well as the study of social networks. This thesis’ specific contribution is the provision of a comprehensive analysis of the roles and characteristics of social networks in relation to their spatiality and temporality, conceptually explored via social capital theory and network-based theory of social capital, and empirically informed via the case of temporary labour migration from Vietnam to South Korea. It approaches this topic by examining (1) how changes to the regulatory framework of contract labour migration between Vietnam and South Korea have resulted in the transformation of migrants’ agency, reflected in the forming and joining of different kinds of networks; (2) the advantages and downsides of the various types of networks involved at different stages of the ‘migration project’; (3) the complexity and changeability of networks engaged in assisting migrants along the entire migration cycle; and (4) the gendered aspects involved in these processes and dynamics. The study relies on a mix of qualitative methodologies in which individual migrant workers are the key units of analysis. The methods for data generation are in-depth interviews and participant observation from fieldwork conducted in Vietnam and South Korea in 2013 and 2015. The findings show that social networks of and for Vietnamese migrant workers, including interpersonal and institutional, are complex and varied. The fundamental purpose of migrant workers generally is to maximise their earnings during a short period of time; they attempt to seek support from different social networks during different phases of their migration. However, not all social networks are supportive and beneficial to the migrants. Some social networks provide opportunities for migrant workers to achieve their goals, while others might aim at exploiting these workers. In other words, assistance can be given free or bought at high costs. Trust and norms of reciprocity exist only among bonding ties, not on a larger scale such as among an entire co-ethnic migrant community. The study also points out that, due to gender segregation of the Korean labour market, men have more opportunities to find a job in this country by contract-based visas, while jobs for women are more limited than their male counterparts. This results in less access to institutional networks for female migrant workers. Since South Korea temporarily suspended contract-based migration from Vietnam, Vietnamese workers have moved to South Korea through other types of visas. The existence of alternative channels for migration to South Korea has gender implications with regard to the type of networks used: male prospective migrants tend to migrate to South Korea through overseas study or trading, whilst their female counterparts find it is easier to enter South Korea through sham marriages or cosmetic surgery. Finally, the study demonstrates the dynamism and the changing nature of social networks that migrants use throughout the migration cycle. Over time, migrants expand their networks locally and transnationally. In addition, the roles of the same networks and the position of migrant workers in these networks may change during different phases of migration. In the case of policies on recruitment of Vietnamese workers for the Korean labour market are often changed, the changing nature of networks also performs in the flexibility of formation of new networks serving for different channels of migration. This unique change of networks reflects is specific policy context of migration between Vietnam and South Korea for making money

Doctor of Philosophy

dissertationHeparan sulfate (HS) chains play roles in numerous biological processes as they bind to various signaling molecules including fibroblast growth factors (FGFs). This graduate research aims at investigating the structural requirements and the biogenesis pathways of FGF8-binding HS motifs. In the first part, the importance of HS multivalency in regulating FGF8 and FGF receptor (FGFR) interactions in vivo was examined. A library of mono-, bis- or trisxylosides was injected into zebrafish embryos to stimulate the production of monomeric, dimeric or trimeric glycosaminoglycan (GAG) chains that are connected covalently, and thereby mimic naturally occurring proteoglycans. Upon their injection, bis- and trisxylosides caused an elongation phenotype whereas mono-xylosides did not. In situ hybridization and other experiments showed that FGF8/FGFR signaling was specifically hyperactivated in elongated embryos. Based on our findings, we propose a molecular model in which two covalently linked GAG chains interact with two FGF8 molecules and their cognate FGFRs and induce FGFR dimerization that leads to the elongation phenotype. This proposed molecular model was reaffirmed by the results of experiments testing syndecan-1 constructs containing zero, one, two or three HS side chains, in which multivalency again demonstrated its essential role in activating FGF8 signaling

Students’ Perceptions and Design Considerations of Flipped Interpreting Classroom

Digital technologies have become a driver of change that exerts tremendous impact across the disciplines, including education. The Flipped classroom model, carried out in a technology-enhanced environment, has been proven to bring educational innovations.  However, in the Vietnamese educational context, the adoption of the flipped model in interpreting courses for undergraduate students has been hardly touched upon in the existing literature. This current study is, therefore, an attempt to examine English-majored students’ perceptions about this teaching model on Moodle Learning Management Platform and put forward some proposals in the design and implementation of the Flipped Interpreting course. The data were collected using both quantitative and qualitative methods, including a Likert-scale questionnaire and individual interviews. The results revealed that students had positive perceptions toward the adoption of Flipped model and Moodle platform. Analyzing the interconnection of three domains in CoI framework and the additional domain of Technology Use, the authors then offer further recommendations for effective implementation of the model in the EFL classroom context

Nuclear Security and HRD - Viet Nam’s Effort

Viet Nam is expanding its nuclear energy program for the application in various areas including industries, agriculture, healthcare, education and research. Recognizing the importance of the nineteen issues laid out in the IAEA document “Milestones in Development of a National Infrastructure for Nuclear Power” [1], Vietnam is considering how to address these issues. This paper describes the establishment of nuclear security infrastructure in Viet Nam and how Viet Nam has addressed one of the nineteen issues, that is human resource development in nuclear energy in general and in nuclear security in particular

Source Evaluation and Trace Metal Contamination in Benthic Sediments from Equatorial Ecosystems Using Multivariate Statistical Techniques

race metals (Cd, Cr, Cu, Ni and Pb) concentrations in benthic sediments were analyzed through multi-step fractionation scheme to assess the levels and sources of contamination in estuarine, riverine and freshwater ecosystems in Niger Delta (Nigeria). The degree of contamination was assessed using the individual contamination factors (ICF) and global contamination factor (GCF). Multivariate statistical approaches including principal component analysis (PCA), cluster analysis and correlation test were employed to evaluate the interrelationships and associated sources of contamination. The spatial distribution of metal concentrations followed the pattern Pb>Cu>Cr>Cd>Ni. Ecological risk index by ICF showed significant potential mobility and bioavailability for Cu, Cu and Ni. The ICF contamination trend in the benthic sediments at all studied sites was Cu>Cr>Ni>Cd>Pb. The principal component and agglomerative clustering analyses indicate that trace metals contamination in the ecosystems was influenced by multiple pollution sources

Chemical examination of Hydrocotyle bonariensis L. (Apiaceae)

Hydrocotyle bonariensis, growing in the Mekong-delta, is used as vegetable and has not yet been chemically studied. From the aerial parts of H. bonariensis, three compounds had been isolated: a triterpene squalene (1) and a mixture of two lignans: hinokinin (2) and α-[3,4-methylendioxy phenylmethylidene]-β-[3,4-methylendioxyphenylmethyl]-γ-butyrolactone (3). The fresh plant was divided into stem-leaf and flower and each part was distilled with steam to afford essential oils. The major components of stem-leaf are: (Z)-3-hexen-1-ol, trans-caryophyllene, α-farnesene, copaene while the major components of flower are: α-pinene, 2-β-pinene, β-myrcene, limonene, α-caryophyllene, epibicyclosesquiphellandrene. The essential oil of the stem-leaf showed cytotoxic activities in vitro on RD and Hep-G2 cancer cells with the IC50 values of 16.1 and 19.9µg/ml, respectively. The study on the plant is being continued

Characteristics of shear strength at the interface between two soil layers in ring shear apparatus

The slopes containing discontinuous planes such as bedding planes, rupture, or boundary between two soil layers are often prone to sliding. Thus, the characteristics of shear strength mobilized along the discontinuous planes should be examined. In this study, the shear strength at the interface between two different soil layers will be investigated based on ring shear test. The combined sample comprising of one kaolin layer and one kaolin + bentonite mixture layer was used to simulate the discontinuous planes between two soil layers. A number of ring shear tests were conducted on these samples at a normal stress of 98 kPa and shear rates from 0.02 to 20 mm/min using a multi-stage of shearing rates procedure. The research results indicate that the shear strength at the interface sharply increases to reach the peak value after a small shear displacement, then drops to the residual value. The residual interface strength tends to increase with increasing shear rates above 2 mm/min and the level of increase in residual interface strength depends on the contact surface. Furthermore, the effect of the order sample layer in combined samples can be ignored when determining the peak, the residual interface strengths as well as the rate effect on residual interface strength in the laboratory

Characteristics of shear strength at the interface between two soil layers in ring shear apparatus

The slopes containing discontinuous planes such as bedding planes, rupture, or boundary between two soil layers are often prone to sliding. Thus, the characteristics of shear strength mobilized along the discontinuous planes should be examined. In this study, the shear strength at the interface between two different soil layers will be investigated based on ring shear test. The combined sample comprising of one kaolin layer and one kaolin + bentonite mixture layer was used to simulate the discontinuous planes between two soil layers. A number of ring shear tests were conducted on these samples at a normal stress of 98 kPa and shear rates from 0.02 to 20 mm/min using a multi-stage of shearing rates procedure. The research results indicate that the shear strength at the interface sharply increases to reach the peak value after a small shear displacement, then drops to the residual value. The residual interface strength tends to increase with increasing shear rates above 2 mm/min and the level of increase in residual interface strength depends on the contact surface. Furthermore, the effect of the order sample layer in combined samples can be ignored when determining the peak, the residual interface strengths as well as the rate effect on residual interface strength in the laboratory