Effects of principals’ leadership styles on teachers’ commitment in Vietnam

In recent years, styles of transformational and transactional leadership have become an important area of research because of its significant impact on teachers’ outcomes such as commitment, job satisfaction, self-efficacy. However, the relationships between transformational and transactional leadership styles of school principals and teachers’ organizational commitment have been rarely investigated in the educational context in Vietnam. This study aimed to determine how transformational and transactional leadership styles influence the organizational commitment of Vietnamese high school teachers. The study employed two standardized surveys to collect data from 387 teachers at 24 public high schools in the Mekong Delta of Vietnam. The results of correlation coefficient analyses indicated that teachers’ organizational commitment was positively influenced by transformational leadership and negatively influenced by transactional leadership. In addition, the results of multiple regression analyses showed that the organizational commitment of teachers was predicted by all components of both leadership styles of principals. The present study suggested that school leaders might combine both transformational and transactional leadership styles in their leadership practices to improve teachers’ organizational commitment

The synthetic triterpenoid CDDO-methyl ester modulates microglial activities, inhibits TNF production, and provides dopaminergic neuroprotection

<p>Abstract</p> <p>Background</p> <p>Recent animal and human studies implicate chronic activation of microglia in the progressive loss of CNS neurons. The inflammatory mechanisms that have neurotoxic effects and contribute to neurodegeneration need to be elucidated and specifically targeted without interfering with the neuroprotective effects of glial activities. Synthetic triterpenoid analogs of oleanolic acid, such as methyl-2-cyano-3,12-dioxooleana-1,9-dien-28-oate (CDDO-Me, RTA 402) have potent anti-proliferative and differentiating effects on tumor cells, and anti-inflammatory activities on activated macrophages. We hypothesized that CDDO-Me may be able to suppress neurotoxic microglial activities while enhancing those that promote neuronal survival. Therefore, the aims of our study were to identify specific microglial activities modulated by CDDO-Me <it>in vitro</it>, and to determine the extent to which this modulation affords neuroprotection against inflammatory stimuli.</p> <p>Methods</p> <p>We tested the synthetic triterpenoid methyl-2-cyano-3,12-dioxooleana-1,9-dien-28-oate (CDDO-Me, RTA 402) in various <it>in vitro </it>assays using the murine BV2 microglia cell line, mouse primary microglia, or mouse primary peritoneal macrophages to investigate its effects on proliferation, inflammatory gene expression, cytokine secretion, and phagocytosis. The antioxidant and neuroprotective effects of CDDO-Me were also investigated in primary neuron/glia cultures from rat basal forebrain or ventral midbrain.</p> <p>Results</p> <p>We found that at low nanomolar concentrations, treatment of rat primary mesencephalon neuron/glia cultures with CDDO-Me resulted in attenuated LPS-, TNF- or fibrillar amyloid beta 1–42 (Aβ1–42) peptide-induced increases in reactive microglia and inflammatory gene expression without an overall effect on cell viability. In functional assays CDDO-Me blocked death in the dopaminergic neuron-like cell line MN9D induced by conditioned media (CM) of LPS-stimulated BV2 microglia, but did not block cell death induced by addition of TNF to MN9D cells, suggesting that dopaminergic neuroprotection by CDDO-Me involved inhibition of microglial-derived cytokine production and not direct inhibition of TNF-dependent pro-apoptotic pathways. Multiplexed immunoassays of CM from LPS-stimulated microglia confirmed that CDDO-Me-treated BV2 cells produced decreased levels of specific subsets of cytokines, in particular TNF. Lastly, CDDO-Me enhanced phagocytic activity of BV2 cells in a stimulus-specific manner but inhibited generation of reactive oxygen species (ROS) in mixed neuron/glia basal forebrain cultures and dopaminergic cells.</p> <p>Conclusion</p> <p>The neuroimmune modulatory properties of CDDO-Me indicate that this potent antioxidant and anti-inflammatory compound may have therapeutic potential to modify the course of neurodegenerative diseases characterized by chronic neuroinflammation and amyloid deposition. The extent to which synthetic triterpenoids afford therapeutic benefit in animal models of Parkinson's and Alzheimer's disease deserves further investigation.</p

Prostaglandin E2 affects differently the release of inflammatory mediators from resident macrophages by LPS and muramyl tripeptides.

LPS and MTP-PE (liposome-encapsulated N-acetyl-muramyl-L-alanyl-D-isoglutaminyl-L-alanine-2-:[1',2'dipalmitoyl -sni-glycero-3-(hydroxy-phosphoryl-oxyl)] etylamide) induce in liver macrophages a synthesis and release of TNF-alpha, nitric oxide and prostanoids. Both agents induce an expression of mRNA's encoding TNF-alpha, inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2, and of corresponding proteins. LPS and MTP-PE induce a rapid activation of the extracellular regulated kinase (ERK) isoenzymes-1 and -2. Inhibition of map kinase isoenzymes leads to a decreased release of TNF-alpha, nitric oxide and prostaglandin (PG) E2 after both agents. The transcription factors NF-kappaB and AP-1 are strongly activated by LPS within 30 minutes. MTP-PE induces a weak activation of both transcription factors only after 5 hours. Inhibition of NF-kappaB inhibits the LPS- but not the MTP-PE-induced release of TNF-alpha, nitric oxide and PGE2. PGE2 release after LPS is higher than after MTP-PE. Exogenously added PGE2 inhibits the activation of map kinase and TNF-alpha release by LPS, but not by MTP-PE. Release of nitric oxide after LPS and MTP-PE is enhanced after prior addition of PGE2. PGD2 is without any effect. MTP-PE, but not LPS, induces a cytotoxicity of Kupffer cells against P815 tumor target cells. The MTP-PE-induced cytotoxicity is reduced by TNF-alpha neutralizing antibodies, indicating the involvement of TNF-alpha. Thus our results suggest that the different potencies of LPS and MTP-PE as immunomodulators probably result from different actions on Kupffer cells, resulting in differences in the amounts and kinetics of released TNF-alpha and PGE2, and that PGE2 plays an important regulatory role in the action of LPS, but not in the actions of MTP-PE

Nanoporous alumina templates : anodisation and mechanical characterisation

Due to applications in electronics, optoelectronics, energy storage, photocatalysis, photonics and biosensors/biomaterials, interest in onedimensional nanostructures has grown significantly during the last decade. The use of nanoporous templates as matrices for fabrication of nanostructures is now commonplace in microelectronics technology. Studies on semiconductors and dielectrics have introduced nanoporous anodised aluminium oxide as a very promising template material for the deposition of nanostructures. It is formed of an array of closely packed hexagonal oxide cells, in the centre of each of which there is a vertical hollow channel, fabricated by simple electrochemical anodisation. Anodisation, an economically viable electrochemical process, has been extensively investigated over a number of years to obtain protective and decorative films on an Al surface. The advantages in using these templates are controllability of the pore size, ratio aspect and use of low cost and simple equipment. Nanoindentation, a method that makes use of very low loads in the millinewton range has been widely used for measuring mechanical properties such as the hardness and Young’s modulus of test samples. In the first part of this chapter, the anodisation of alumina templates, as well as the electrochemical process parameters and mechanisms are discussed by means of structural and morphological characterisation. The second part is dedicated to the study of mechanical properties of nanotemplates using nanoindentation.Fundação para a Ciência e Tecnologia and FP7-PEOPLE-2010-IRSES-NanoCIS (269279) project

Electrochemical anodizing, structural and mechanical characterization of nanoporous alumina templates

Highly ordered Anodic Aluminum Oxide (AAO) structures produced from aluminum by using an electrochemical anodizing method were developed towards its application for the next generation of micro/nano medical and energy devices. In addition of analyzing the anodizing current profile, the surface morphology was characterized by using Scanning Electron Microscopy (SEM), the crystalline structure by X-Ray Diffraction (XRD) and the mechanical properties by nanoindentation experiments. The anodizing time and applied potential determines the nanopores regularity and their size, although the effect of the potential is more pronounced than the effect of temperature in the transformation from crystalline alumina to amorphous alumina. Optimum pore growth was achieved with an applied potential of 17 V which led to a pore fraction - P(f) - of about 17.5%. The experimental Berkovich nanoindentation method was used to determine the AAO hardness as a function of the indenter depth, during the loading stage, using mechanical response and deformation behaviour of the nanopores structure. From the experimental data of the loaddisplacement curves, this method allows the calculation of the indenter contact depth at each reloading point, thus leading to the estimation of the material’s hardness. The results reveal that the hardness depends on the processing conditions used for the production of the AAO samples that also strongly influences the organization and pore size uniformity.FCT (Fundação para a Ciência e Tecnologia) for funding through Ciencia 2007 programme and the pluriannual contract with CFUM

Technical efficiency heterogeneity of tertiary institutions in Viet Nam: A metafrontier directional technology approach

The higher education system of Viet Nam has been undergoing reform process with the aim of seeking a position in the world's education market. However, recent changes in the system have made the operational efficiency of the system less stable, thus making it more challenging to improve the country's universities world rankings. In this paper, we investigate the performance of tertiary education institutions in Viet Nam and evaluate the efficiency gap between colleges and universities. Using the metafrontier directional technology approach, we estimate both the group frontier and metafrontier efficiencies for 112 universities and 141 colleges using data for 2011-2013 and compute their differences imposed by the technology associated with different levels of ownership and locations. The findings showed that the performance of universities were better than that of colleges, at 0.837 0.774, respectively. However, under an unrestricted metafrontier framework, the metatechnology ratios suggest that universities and colleges were operated comparatively well by potentially increasing their performance by 7.8 and 5.0 per cent, respectively. Both urban universities and colleges are found to be more efficient than their rural counterparts, but the effects of ownerships showed mixed results on the performance of universities and colleges. Our results highlight the need for appropriate policies and enabling environment that will enhance the performance of each institution. It is imperative to re-evaluate the specific role and individual contributions of colleges and universities in the national education system and assist rural universities and colleges to explore their full potential to enhance their performance

Technical efficiency heterogeneity of tertiary institutions in Viet Nam: a metafrontier directional technology approach

The higher education system of Viet Nam has been undergoing reform process with the aim of seeking a position in the world’s education market. However, recent changes in the system have made the operational efficiency of the system less stable, thus making it more challenging to improve the country’s universities world rankings. In this paper, we investigate the performance of tertiary education institutions in Viet Nam and evaluate the efficiency gap between colleges and universities. Using the metafrontier directional technology approach, we estimate both the group frontier and metafrontier efficiencies for 112 universities and 141 colleges using data for 2011–2013 and compute their differences imposed by the technology associated with different levels of ownership and locations. The findings showed that the performance of universities were better than that of colleges, at 0.837 0.774, respectively. However, under an unrestricted metafrontier framework, the metatechnology ratios suggest that universities and colleges were operated comparatively well by potentially increasing their performance by 7.8 and 5.0 per cent, respectively. Both urban universities and colleges are found to be more efficient than their rural counterparts, but the effects of ownerships showed mixed results on the performance of universities and colleges. Our results highlight the need for appropriate policies and enabling environment that will enhance the performance of each institution. It is imperative to re-evaluate the specific role and individual contributions of colleges and universities in the national education system and assist rural universities and colleges to explore their full potential to enhance their performance. First published online 17 September 201