Showing papers by "Mahidol University International College published in 2010"
TL;DR: Para-Regioselective bromination of phenol and analogues, promoted by p-toluenesulfonic acid, is achieved in high to excellent yields at room temperature with N-bromosuccinimide as discussed by the authors.
40 citations
TL;DR: In this article, the Santi Asoke Buddhist group represents, what the "Dharma Army" is, how its reality differs from media images, and why the group finally turned against Thaksin Shinawatra.
Abstract: Thailand experienced dramatic political turmoil from February 2006 to November 2008 culminating in the occupation of the Bangkok International Airport. The demonstrations against then Prime Minister Thaksin Shinawatra and his political allies were organised by the People’s Alliance for Democracy (PAD). One of the PAD leaders, Major-General Chamlong Srimuang, is an active member of the Buddhist Santi Asoke group. The group is controversial as it is not under the state Buddhist authorities and has implicitly criticised the Thai state Buddhist monks for moral corruption. Known as the ‘Dharma Army’, hundreds of Santi Asoke monks, nuns and lay people participated in PAD demonstrations. This paper analyses what the Santi Asoke Buddhist group represents, what the ‘Dharma Army’ is, how its reality differs from media images, what the ideological reasons for Asoke to initially support Thaksin were, and why the group finally turned against him. The paper argues that the group cannot be viewed as a monolithic community. Instead, it should be considered as an amalgamation of monks and nuns, urban and rural temple residents, lay followers of Asoke monks, practitioners of organic agriculture in Asoke village communities, students and former students of Asoke schools, and supporters of Major-General Chamlong Srimuang. Representatives of all these networks participated in the demonstrations albeit with different intensity.
18 citations
TL;DR: In this article, the effects of bias voltage placed on a second gate which is positioned to the left of the FG layer on the switching of the charge and spin transports in a ferromagnetic graphene junction are studied.
Abstract: The effects of the bias voltage placed on a second gate which is positioned to the left of the ferromagnetic graphene (FG) layer on the switching of the charge and spin transports in a ferromagnetic graphene junction are studied. We show that the change in the bias voltage from positive to negative (while maintaining the positive voltage on the first gate above the FG layer) can induce a switching from high to low conductance states in the junction. The voltage on the first gate is used to shift the Fermi level in the FG layer. Enhancement of the on/off conductance ratio on the switching is shown to be inversely proportional to the thickness of the second gate barrier. We show that by biasing the nanostructures with the voltage U2, the spin polarization can be increased and that as a consequence, the thickness of the FG barrier layer needed for spin-polarized transport can be reduced.
17 citations
TL;DR: A monkey population allied to Francois' leaf monkey Trachypithecus francoisi discovered in 1920 constitutes the taxon laotum, endemic to Lao PDR.
Abstract: A monkey population allied to Francois' leaf monkey Trachypithecus francoisi discovered in 1920 constitutes the taxon laotum, endemic to Lao PDR. The next seven decades provided very little additional information about it. Wildlife surveys in the 1990s found a large population of T. (f.) laotum in Phou Hinpoun (=Khammouan Limestone) National Protected Area (NPA) and north into southern Nam Kading NPA, and a large population in and around Hin Namno NPA of T. (f.) ebenus, known outside Lao PDR only from adjoining Vietnam. Detailed here are confirmed records of smaller and more localized populations of leaf monkeys of the T. francoisi group (sensu Groves 2001, 2005, p. 175) from two other areas (Nakai—Nam Theun NPA and a region outside the protected area system, Muang (= District of) Vilabouli, in Savannakhet province), highly plausible reports from one more site, and records of T. (f.) ebenus from southern Phou Hinpoun NPA. Animals from Nakai—Nam Theun NPA and Muang Vilabouli differ in pelage from...
12 citations
TL;DR: In this paper, six different estimating strategies are employed to explore ex-post-portfolio performance when estimation risk is incorporated, and the shrinkage estimators incorporating the single index model outperform other traditional portfolio selection strategies.
Abstract: Efficient portfolio is a portfolio that yields maximum expected return given a level of risk or has a minimum level of risk given a level of expected return. However, the optimal portfolios do not seem to be as efficient as intended. Especially during financial crisis period, optimal portfolio is not an optimal investment as it does not yield maximum return given a specific level of risk, and vice versa. One possible explanation for an unimpressive performance of the seemingly efficient portfolio is incorrectness in parameter estimates called “estimation risk in parameter estimates”. Six different estimating strategies are employed to explore ex-post-portfolio performance when estimation risk is incorporated. These strategies are traditional Mean-Variance (EV), Adjusted Beta (AB) approach, Resampled Efficient Frontier (REF), Capital Asset Pricing Model (CAPM), Single Index Model (SIM), and Single Index Model incorporating shrinkage Bayesian factor namely, Bayesian Single Index Model (BSIM). Among the six alternative strategies, shrinkage estimators incorporating the single index model outperform other traditional portfolio selection strategies. Allowing for asset mispricing and applying Bayesian shrinkage adjusted factor to each asset's alpha, a single factor namely, excess market return is adequate in alleviating estimation uncertainty.
10 citations
TL;DR: The results of this study show that duplex RT-PCR is an easy, rapid, sensitive, and reproducible method, which is particularly valuable when numerous samples must be analyzed, and may usefully serve as an alternate tool for diagnosing TE in severely immunocompromised patients.
9 citations
TL;DR: In this paper, the effects of the superconducting energy gap in SG, of the gap mv F 2 which opened in the super-conducting graphene, of exchange field in FG, of spin-dependent specular Andreev reflection, and of the effective Fermi energy (E FF ) of FG and of bias voltage across the junction (V ) are simulated.
Abstract: With the fabrication of gapped graphene, interest in the tunneling spectroscopy in graphene-based FG/SG junctions in which one side consists of a gapless ferro-magnetic graphene (FG) and the other side, of a gapped superconducting graphene (SG) has arisen. The carriers in the gapless (gapped) graphene are 2D relativistic particles having an energy spectrum given by E = ℏ 2 v F 2 k 2 + ( mv F 2 ) 2 (where mv F 2 is the gap and v F is the Fermi velocity). The spin currents in this FG/SG junction are obtained within the framework of the extended Blonder–Tinkham–Klapwijk (BTK) formalism. The effects of the superconducting energy gap in SG, of the gap mv F 2 which opened in the superconducting graphene, of the exchange field in FG, of the spin-dependent specular Andreev reflection, of the effective Fermi energy ( E FF ) of FG and of the bias voltage across the junction ( V ) are simulated. It is seen that by adjusting E FF or V , the spin polarization (defined as SP(%) = 100% × ( G ↑ − G ↓ )/( G ↑ + G ↓ )) can be switched from a pure spin up (SP = +100%) state to pure spin down (SP = −100%) state.
7 citations
TL;DR: In this article, the authors adopt the hedonic price approach to quantify the brand equity of information and communication technology (ICT) products, narrowed down to laptop computers, laser printers, liquid crystal display computer screens, and mobile phones.
Abstract: Purpose – The paper aims to adopt the hedonic price approach to quantify the brand equity of information and communication technology (ICT) products, narrowed down to laptop computers, laser printers, liquid crystal display computer screens, and mobile phones.Design/methodology/approach – The hedonic price model features the list price as the dependent variable of the regression, whilst the measurable attributes of the product and brand dummies are on the right‐hand side. Additionally, the model can be adjusted to measure brand effects on profit margins as well.Findings – In most of the price and log price models, brand dummies are significant, and positively linked to the consumers' willingness to pay. Nevertheless, amongst the four ICT products in this study, only the laptop brands show positive values. Negative but significant brand dummies suggest that brands are undoubtedly important; however, other features exhibit higher value to consumers.Research limitations/implications – As is the case with oth...
2 citations
TL;DR: Industrial thermostable α-amylase with a suitable degree of glycation, can be more efficient in hydrolytic process and found to be more stable than the native form.
Abstract: Glycation of the thermostable α-amylase, KLE, from Bacillus subtilis occurred during incubation with maltodextrin at 95C. This was revealed by the release of 5-hydroxymethyl-2-furfuraldehyde from the acid hydrolysis of glycated KLE (gKLE), the differences in the protein band patterns on SDS and Native-PAGE, and the shifting of the pI value from the range of 5.6–6.5 to that of 5.2–6.5. After glycation, the activity of gKLE was still retained. Furthermore, gKLE was more resistant to heat and pH compared with the nonglycated enzyme. The Km, reaction rate and efficiency to convert gelatinized cornstarch into maltodextrin of KLE were remained unchanged after glycation. This was different from the result obtained for BAN, another thermostable α-amylase produced by B. amyloliquefaciens. Glycation in BAN decreased the activity in converting gelatinized cornstarch into maltodextrin. Moreover, the stability and kinetic parameters of BAN were found to be negatively affected by glycation.
PRACTICAL APPLICATIONS
One of the major applications of starch is for the production of glucose, either in a form of crystalline or syrup which can be further processed into high-fructose syrup. This is done by starch hydrolysis which is composed of two major enzymatic steps, i.e., liquefaction and saccharification. Liquefaction, converting gelatinized starch to maltodextrin, is carried out by the action of thermostable α-amylase, while saccharification is by glucoamylase. During the process under the conditions of high concentration of reducing sugar and high temperature, thermostable α-amylase can be glycated. This non-enzymatic process occurs when reducing sugar and free amino groups are coexisted in the system. However, the glycated enzyme was found to be more stable than the native form. Hence, industrial thermostable α-amylase with a suitable degree of glycation, can be more efficient in hydrolytic process.
2 citations
TL;DR: In this article, the phase difference dependence of the critical Josephson current in a parallel aligned junction indicated a cross over from a 0-state to a π-state whenever the ferromagnetic barrier strength χ ex is equal to (n/2+n/0.25) π (with n ǫ = 1, 2, 4)
Abstract: The Josephson current in a double ferromagnetic layer SG/F 1 /F 2 /SG graphene junction where the SG’s are graphene-based s-wave superconductors and the F 1,2 are ferromagnetic layers of thicknesses d 1,2 in which the exchange energies are E ex 1,2 , is studied. The Josephson current in this junction is composed of Cooper pairs formed by quasi particles which are massless Weyl–Dirac electrons. By switching the alignment of the two exchange fields, we find that the Josephson current in the junction can change from being in the π -state to being in the 0-state. For the case where the magnitudes of the exchange field strength are the same, it is seen that the phase difference dependence of the critical Josephson current in a parallel aligned junction indicated a cross over from a 0-state to π -state whenever the ferromagnetic barrier strength χ ex is equal to ( n /2 + 0.25) π (with n = 1, 2, …). The AP-junction for F 1 = F 2 behaves as if it has no the magnetic barriers, like S/N/S junction. It is also seen that the temperature dependence of the (%) magneto-Josephson current ratio defined as the difference between the critical currents of the graphene-based P-junction and AP-junctions defined as, % P S ∼ ( 100 % ) x ( I P c - I AP c ) / I P c , is found to be oscillated under varying the exchange energies. The maximum value of % P S , (max) P S → − ∞ as T → T C . The cause of these effects is the relativistic nature of the quasi particles in the graphene-based junctions.
2 citations
TL;DR: In this article, the authors investigated the magneto effect on the transport property of a F/(FS) junction where F is a ferromagnetic gapless graphene and FS is achieved by depositing a conventional s-wave superconductor on the top of gapped graphene sheet.
Abstract: Coexistence of superconductivity and ferromagnetism in a gapped graphene-based system (FS) is theoretically investigated. The center-of-mass momentum, P, of a Cooper pair in FS is found to be P ∼ 2 E ex / ℏ v F 1 - ( m / E FS ) 2 , where m, Eex, EFS are the rest mass energy of the Dirac electron, exchange energy and the Fermi energy in the superconductor FS, respectively. It is unlike the nature in a conventional FFLO state where P ∼ 2 E ex / ℏ v F . This work studies the magneto effect on the transport property of a F/(FS) junction where F is a ferromagnetic gapless graphene. In this work, FS is achieved by depositing a conventional ferromagnetic s-wave superconductor on the top of gapped graphene sheet. The Zeeman splitting in FS induces spin-dependent Andreev resonance. The conductances effected by both spin-dependent specular Andreev reflections and spin-dependent Andreev resonances are investigated. The interplay between the spin-dependent specular Andreev reflection in the F region and the spin-dependent Andreev resonance in the FS region causes a very large tunneling magnetoresistance |TMR| ∼ 3000% for m → EFS, possibly valuable in the graphene-based spintronic devices. This is because of the coexistence of the superconductivity and ferromagnetism in FS and the relativistic nature of electrons in graphene.