532 research outputs found
Enhancing functional production of a chaperone-dependent lipase in Escherichia coli using the dual expression cassette plasmid
Vietnam and the great powers
Ausgehend von der Doi moi Poltik - einer Wirtschaftsreform die 1986 begann - hatte
Vietnam seine grundsĂ€tzliche auĂenpolitische Linie, im speziellen sein politisches
Verhalten gegenĂŒber den GroĂmĂ€chten, anzupassen. Diese Arbeit möchte die
entscheidenden Faktoren, die zu groĂen VerĂ€nderungen in der vietnamesischen
AuĂenpolitik seit 1986 fĂŒhrten und die strategischen Ziele die Hanoi in den
Beziehungen zu den GroĂmĂ€chten verfolgt (USA, China, EuropĂ€ische Union,
Russland, Japan und Indien), analysieren. Ich behaupte, dass die vietnamesische
AuĂenpolitik gegenĂŒber den GroĂmĂ€chten seit Doi moi einer Mischung von
zwei theoretischen Paradigmen zusammensetzt: Realismus und Liberalismus. Die
pragmatischen AnsÀtze Hanois sind Mittel zum Zweck um der Modernisierung und der
Industrialisierung des Landes zu dienen. Diese Fallstudie ĂŒber Vietnam versucht ein
Beispiel dafĂŒr zu geben wie klein und mittelgroĂe Staaten SĂŒdostasiens auf die
heutigen GroĂmĂ€chte, in der Zeit seit Ende des Kalten Krieges, reagieren. Ebenso wie
die bekanntesten ZugÀnge westlicher Theorien im Bereich der internationalen
Beziehungen dazu dienen, die AuĂenpolitik eines sĂŒdostasiatischen Landes, in diesem
Fall Vietnam, zu erforschen.Deriving momentum from Doi moi-an economic reform launched since 1986, Vietnam
has to adjust its general foreign policy, especially its policy behaviors toward the great
powers. This thesis aims to examine determinant factors leading to significant changes
of the in Vietnamese foreign policy since 1986, and strategic approaches which Hanoi
has been pursuing in dealing with the present-day great powers (the United States,
China, the European Union, Russia, Japan and India). I argue that Vietnamese foreign
relations toward the great powers since Doi moi can be configured by a mixture of two
theoretical paradigms: realism and liberalism. Hanoiâs pragmatic approaches are aims
to serve for the cause of national modernization and industrialization. This case study
about Vietnam attempts to give an example of understanding how small and medium
sized states in South East Asia respond to the present-day great powers in the post-
Cold War era. And how mainstream approaches in Western theory of international
relations make sense in identifying foreign relation pattern of a South East Asia
country-Vietnam
Vietnam and the ASEAN Socio-Cultural Community (ASCC): Prospects, Challenges and Opportunities
Although there is a large literature on ASEAN regionalism, comparatively little attention has been devoted to Southeast Asiaâs efforts to build a shared social and cultural community. This thesis examines how the ASEAN Socio-Cultural Community (ASCC) is understood in ASEAN and explores challenges that stand in the way of the Community being realized by its 2015 deadline. The study reviews the origins and response to the ASCC at both the regional level, and at the national level through a case-study of Vietnamâs participation. It argues that although the ASCC is an important component of the ASEAN Community building process and member states have proclaimed their determination to realize the ASCC by 2015, the reality in ASEAN with its âunity in diversityâ and âASEAN Wayâ norms, means there are many obstacles in the way. Divergent national interests and priorities have led to different priorities in designing and implementing the ASCC Blueprint in the period 2009-2015. The thesis concludes by speculating about the likely scenario for ASCC implementation. It argues that in 2015, the most likely scenario for the ASCC is one in which a nascent ASCC will be formed but with only some of its components in place. ASEAN needs a longer journey to realize its aspiration of a shared socio-culture community
Simulation du Comportement sous Irradiation aux Ions Lourds du Nanocomposite Au-SiO2
Metal-glass nanocomposites are interesting owing to their particular optical-properties. Ion irradiation can be used as a tool to fabricate nanocomposites. The aim of this thesis was to study, from a fundamental point of view, the behavior of gold nanoparticles (NPs) embedded in an amorphous silica matrix under irradiation. My contribution consists in the interpretation, by modeling and numerical simulation, of experimental results previously obtained by researchers of the Laboratoire des Solides IrradiĂ©s. In a first type of experiments, the system was irradiated with 4 MeV gold ions while in a second type the irradiation was performed by using 74 MeV krypton ions.For the study of the first type of experiments, the simulation by kinetic Monte Carlo (KMC) on rigid lattice was chosen and developed specifically to study the behavior of NPs irradiated at different temperatures. The simulations allows us to reproduce qualitatively the experimental results at any temperature. We found that the system evolves within a direct coarsening regime at high temperature (T>900 K) whereas at low temperatures (T60 nm) by the incident ions. We imagined a scenario for the mechanism of deformation which is based on the thermal expansion of the melted NP into the track produced by the incident ion in the matrix. Its implementation using a new simulation technique helped to refine certain elements of the scenario and to improve the overall understanding of the process. The qualitative agreement between the experimental data and the results obtained by the simulation validate the proposed mechanism.Les matĂ©riaux nanocomposites de type mĂ©tal-verre sont intĂ©ressants en raison de leurs propriĂ©tĂ©s optiques particuliĂšres. La technique de fabrication utilisant les faisceaux dâions est un outil prometteur pour les nanocomposites. Lâobjectif de cette thĂšse Ă©tait dâĂ©tudier dâun point de vue fondamental le comportement sous irradiation de nanoparticules (NPs) dâor enfouies dans une matrice de silice amorphe. Ma contribution rĂ©side dans lâinterprĂ©tation par modĂ©lisation et simulation numĂ©rique des rĂ©sultats expĂ©rimentaux obtenus auparavant par des chercheurs du Laboratoire des Solides IrradiĂ©s. Dans le premier type dâexpĂ©riences, le systĂšme a Ă©tĂ© irradiĂ© par des ions dâor de 4 MeV alors que dans le second type lâirradiation est effectuĂ©e avec des ions de krypton de 74 MeV.Dans la premiĂšre partie, la simulation par Monte Carlo cinĂ©tique (KMC) sur rĂ©seau rigide a Ă©tĂ© choisie et dĂ©veloppĂ©e spĂ©cifiquement pour Ă©tudier le comportement de NPs sous irradiation Ă diffĂ©rentes tempĂ©ratures. Les simulations ont permis de reproduire qualitativement les rĂ©sultats expĂ©rimentaux Ă toute tempĂ©rature. Nous avons retrouvĂ© en particulier le mĂ»rissement dâOstwald qui se produit Ă haute tempĂ©rature (T>900 K) et la dissolution des NPs qui se produit Ă basse tempĂ©rature (T60 nm) selon lâaxe de lâion incident. Nous avons imaginĂ© un scĂ©nario du mĂ©canisme de la dĂ©formation qui repose sur la dilatation thermique de la NP mĂ©tallique fondue dans la rĂ©gion de la trace de lâion incident. Sa mise en Ćuvre, grĂące Ă une nouvelle technique de simulation dĂ©veloppĂ©e spĂ©cialement, a permis dâaffiner certains Ă©lĂ©ments du scĂ©nario et dâamĂ©liorer la comprĂ©hension globale du processus. Lâaccord qualitatif entre les donnĂ©es expĂ©rimentales et les rĂ©sultats obtenus par simulation valide le mĂ©canisme proposĂ©
Effect of deposition time on gold nanodendrite porous structure and on signals of Hg(II) in environment
The influences of deposition time (tdep) for Au nanodendrite preparation on carbon cloth electrodes on the surface structure, electrochemical behavior and voltammetric signal for Hg(II) detection have been studied. The obtained results showed that from 60 s to 300 s, the longer deposition time, the larger dendrite length as well as the more increased density of dendrite structure became. Calculated from data showed that the electroactive surface area approached to the maximum value of 3.686 cm2 with tdep = 300 s. The typical electrochemical behaviour of the prepared electrodes was mass transfer diffusion to the electrode surface and being considered as planar diffusion. Using DPASV technique, the peak height of Hg(II) could appoach to 52 ”A with tdep = 60 s. Keywords. Gold nanodendrite, deposition time, surface structure, electrochemical properties, mercury
Transformation Chlorophyll a of Spirulina platensis to Chlorin e6 Derivatives and Several Applications
BACKGROUND: Spirulina platensis contains a large amount of chlorophylls, chlorophyll a, that are starting materials to synthesize functionalized chlorins. Chlorin e6 (Ce6) as well as its derivatives are second generation sensitizers using in photodynamic therapy (PDT) of various cancers. In this study, we transfer chlorophyll a of S. platensis to Ce6derivatives and determine their several applications.
AIM: to evaluate the effects of Ce6 derivatives to treat cancer cells.
METHODS: Ce6 trimethylester was created from methyl pheophorbide a2 in S. platensis provided by the Hidumi Company, Nghe An province, Viet Nam. Hela cells were incubated with Ce6 trimethylester and the irradiated with the diode laser dose of 1.2 J/cm2/min through the system of filters ĂÂŁ 650 nm. MTT assay and clonogenic assay were used to determine survival rate and cloning efficiency of cells. Antimicrobial effect of Ce6 trimethylester with halogen light were studied with Propionibacterium acnes VTCC 0218 and Staphylococcus aureus VTCC 0173.
RESULTS: From dry biomass (700 g) of S. platensis, after extracting chlorophyll a and methanolysis, 4.2 g of methyl pheophorbide a was obtained. The reaction to give Ce6 trimethylester with 82% yield was performed with potassium hydroxide (KOH) in MeOH/THF/CHCl3. After irradiation with a 650 nm laser at 1.2 J, the cell viability in all samples decreased with Ce6 trimethylester treatment, the survival declining trend of Hela cells treated with Ce6 trimethylester were proportional when concentration of Ce6 trimethylester increased. The rate of colony formation was declined as the concentration of Ce6 trimethylester treated was increased. The growth of both S. aureus and P. acnes can be inactivated by Ce6 trimethylester PDT. The MIC99 value against P. acnes VTCC 0218 and S. aureus VTCC 0173 of Ce6 trimethylester with halogen light was 1.25 ĂÂŒg/ml.
CONCLUSION: The Ce6 trimethylester from S. platensis cultivated in Viet Nam could be used as a potential photosentizer for photodynamic therapy for treatment of cancer and acne
Evaluation of Pseudomonas stutzeri AM1 and Pseudomonas oleovorans ST1.1 isolated from shrimp pond sediments as probiotics for whiteleg shrimp, Litopenaeus vannamei culture
This study aimed to isolate the probiotic potential of nitrifying bacterial strains and to evaluate their effects on water quality and growth performance of the whiteleg shrimp, Litopenaeus vannamei. Based on an initial screening of 100 isolates identified from sediment samples, 12 strains could remove nitrogen compounds and two strains (Pseudomonas stutzeri AM1 and P. oleovorans ST1.1) showed highly efficient nitrogen removal ability. Within 96 h, total ammonia nitrogen (TAN) removal efficiency in the two strains was 28.0-31.6% and 21.5-24.9%, respectively. The water addition of 103 CFUmL-1 of P. stutzeri AM1 (T1) and P. oleovorans ST1.1 (T2) effectively reduced TAN, nitrite, nitrate, and total sulfide and increased the survival rate and biomass of shrimp. However, no significant differences were found between the control (T0) and treatment groups (T1 and T2) in the final weight, weight gain and specific growth rate of shrimp. Overall, P. stutzeri AM1 (T1) and P. oleovorans ST1.1 used as water supplements improved water quality and the survival rate of whiteleg shrimp
Preschool STEM Activities and Associated Outcomes: A Scoping Review
This review highlights the need for further investigation into the benefits of STEM activities in preschool childrenâs learning, girlsâ engagement and learning of children with disabilities in the STEM field. The review process involved accessing 19 relevant studies from Scopus, ERIC and Google Scholar databases in March 2023. Through the synthesis of information from these studies, seven STEM activities were identified as effective in enhancing preschool childrenâs learning: educational robots, educational games, argumentative interactions, inquiry-based learning and engineering design, drawing and telling about engineers, free play and pretend play, and group membership. Each of these activities contributes to different learning outcomes for children. Moreover, the review emphasizes the importance of role-playing activities âas ifâ engineers and scientists, facilitated by teachers, in fostering girlsâ motivation and engagement in the STEM field from an early age. Long-term scientific interventions at home have a significant positive impact on the science literacy skills of deaf children. The implications of this review are particularly relevant for early childhood educators, as it provides valuable insights into the use of STEM activities to enhance childrenâs learning outcomes
DEWATS dissemination in Vietnam: achievements and lessons learnt
The speedy economic development and rapid growth of population and urbanization in Vietnam have created great pressure on the environment by its manufacturing process and human activities. Thus, it is necessary to protect the environment through policies and appropriate technology for the sustainable development of the country. The DEcentralized WAstewater Treatment Solutions (DEWATS) dissemination in Vietnam is one of the measures contributing to address this issue
Robust adaptive controller for wheel mobile robot with disturbances and wheel slips
In this paper an observer based adaptive control algorithm is built for wheel mobile robot (WMR) with considering the system uncertainties, input disturbances, and wheel slips. Firstly, the model of the kinematic and dynamic loops is shown with presence of the disturbances and system uncertainties. Next, the adaptive controller for nonlinear mismatched disturbance systems based on the disturbances observer is presented in detail. The controller includes two parts, the first one is for the stability purpose and the later is for the disturbances compensation. After that this control scheme is applied for both two loops of the system. In this paper, the stability of the closed system which consists of two control loops and the convergence of the observers is mathematically analysed based on the Lyapunov theory. Moreover, the proposed model does not require the complex calculation so it is easy for the implementation. Finally, the simulation model is built for presented method and the existed one to verify the correctness and the effectiveness of the proposed scheme. The simulation results show that the introduced controller gives the good performances even that the desired trajectory is complicated and the working condition is hard
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