Manila, Philippines

Philippine Normal University
Manila, Philippines

The Philippine Normal University is a public research university in Manila, Philippines established during the early days of American colonial rule. Pursuant to Republic Act No. 9647, it is now funded and operated as a National Center for Teacher Education in the country. Wikipedia.

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Arevalo R.L.,Osaka University | Arevalo R.L.,Philippine Normal University | Escano M.C.S.,University of Fukui | Kasai H.,Osaka University
ACS Catalysis | Year: 2013

Recent theoretical and experimental findings have motivated the use of 3d transition metals as alloying elements to improve the performance of Au for the electro-oxidation of borohydride. In this paper, we provide mechanistic insights into the electrochemical oxidation of borohydride on pure Au and Au-3d alloys (Au3M with M = Cr, Mn, Fe, Co, Ni) using first principles calculations. We found that the initial oxidative adsorption of borohydride is the least exothermic among the elementary reactions considered for the complete eight-electron oxidation process. Interestingly, Au-3d metal alloy surfaces promote this oxidation step at a lower electrode potential compared to pure Au due the enhanced stability of borohydride on these alloy surfaces. The most negative borohydride oxidation potential is achieved by M = Co, followed by Fe, Ni, Mn, and Cr in order of increasing electrode potential. Subsequent to the initial oxidative adsorption of borohydride, the dehydrogenations of BH 3*, BH2OH*, and BH(OH)2* are endothermic on pure Au at very low potentials. However, these activated and possibly limiting elementary reaction steps are more exothermic on Au-3d alloys than on pure Au. Following the adsorption of borohydride on the surface, all elementary reaction steps for the complete electro-oxidation process proceed downhill in energy at a lower electrode potential on Au-3d alloys than on pure Au. © 2013 American Chemical Society.

Xiang C.-L.,CAS Kunming Institute of Botany | Funamoto T.,Showa Pharmaceutical University | Evangelista E.V.,Philippine Normal University | Zhang Q.,CAS Institute of Botany | Peng H.,CAS Kunming Institute of Botany
Plant Biosystems | Year: 2013

Pollen grains of 15 taxa of the genus Chelonopsis (14 spp. and 1 variety) from China and Japan and 6 species of the closely related genera Bostrychanthera (1 species) and Gomphostemma (5 species) were examined by light and scanning electron microscopy. Of these, the pollen morphology of 18 taxa was studied for the first time. Pollen grains were found to be tricolpate with polar lengths of 20.8-30.0 μm and equatorial widths of 17.5-27.3 μm. The basic shape of the pollen in most taxa is subprolate or prolate-spheroidal, but spheroidal, subprolate-spheroidal, oblate-spheroidal, and prolate-subprolate grains are also found in some species. The surface is generally reticulate or suprareticulate in Chelonopsis and granulate in Bostrychanthera. In comparison with those of Chelonopsis and Bostrychanthera, the pollen grain surfaces of Gomphostemma are more diverse. In Chelonopsis, pollen is taxonomically useful at the sectional level, and some grains provide enough characters for species delimitation. The potential pollination ecology of cellular hairs on the anthers of Chelonopsis and Bostrychanthera is also briefly discussed. © 2013 Società Botanica Italiana.

Arevalo R.L.,Osaka University | Arevalo R.L.,Philippine Normal University | Escano M.C.S.,Osaka University | Wang A.Y.-S.,University of British Columbia | Kasai H.,Osaka University
Dalton Transactions | Year: 2013

We study the adsorption of borohydride on Au and Au-based alloys (Au 3M with M = Cr, Mn, Fe, Co, and Ni) using first-principles calculations based on spin-polarized density functional theory. Favorable molecular adsorption and greater adsorption stability compared to pure Au are achieved on Au3M alloys. For these alloys, there is an emergence of unoccupied states in the surface d band around the Fermi level with respect to the fully occupied d band of pure Au. Thus, the derived antibonding state of the sp-d interaction is upshifted and becomes unoccupied compared to pure Au. The B-H bond elongation of the adsorbed borohydride on these alloy surfaces points to the role of surface-parallel (dxy and d x2-y 2 states) components of the d-band of the alloying metal M, most pronouncedly in the cases of M = Co or Ni. On the alloy surfaces, B binds directly with the alloying metal, unlike in the case of pure Au where the surface bonding is through the H atoms. These results pose relevant insights into the design of Au-based anode catalysts for the direct borohydride fuel cell. © 2013 The Royal Society of Chemistry.

Morales M.P.E.,Philippine Normal University
Journal of Science Education and Technology | Year: 2015

“Culture,” a set of principles that trace and familiarize human beings within their existential realities, may provide an invisible lens through which reality could be discerned. Critically explored in this study is how culture- and language-sensitive curriculum materials in physics improve Pangasinan learners’ attitude toward science. Their cultural preference or profile defined their cultural dimensions, epistemological beliefs, and views on integration of culture and language in the teaching and learning processes. The culture- and language-influenced curriculum materials in physics were heavily influenced by Pangasinan learners’ cultural preference or profile. Results of the experimental participants’ pretest and posttest on science attitude measure, when compared, showed significant statistical difference. Assessment of science attitude enhancement favored the experimental group over the control group. Qualitative data gathered from postimplementation interviews, focus group discussions, and journal log entries indicated the same trend in favor of the experimental participants. The study yielded that culture and language integration in the teaching and learning processes of physics concepts allowed students to develop positive attitude to science, their culture, and native language. © 2015 Springer Science+Business Media New York

Arevalo R.L.,Osaka University | Arevalo R.L.,Philippine Normal University | Oka K.,Osaka University | Nakanishi H.,Osaka University | And 4 more authors.
Catalysis Science and Technology | Year: 2015

Platinum is commonly used as a catalyst for the oxidation of NO in exhaust gas purification systems. However, in addition to its high cost, the intrinsic NO + O → NO2 reaction is endothermic and the rate-limiting O2,gas dissociative adsorption is activated on Pt(111). In this paper, we show for the first time that the pseudomorphic Pt monolayer on 3d transition metals promotes a thermodynamically and kinetically favorable NO oxidation compared to pure Pt. Using density functional theory-based first principles calculations, we show that such results are attributed to the weaker binding of O and NO on the bimetallic surfaces and the change of the binding configuration of NO2 into a structure that promotes easier N-O bond formation. These results provide insights into the design of low-cost and efficient catalysts for NO oxidation. © The Royal Society of Chemistry 2015.

Cahyanto W.T.,Osaka University | Escano M.C.,Osaka University | Kasai H.,Osaka University | Arevalo R.L.,Osaka University | Arevalo R.L.,Philippine Normal University
e-Journal of Surface Science and Nanotechnology | Year: 2011

We present a density functional theory calculation for the adsorption and dissociation of OOH on Pt(111) and Pt(111)-alloy surfaces. We confrmed the theoretical understanding of an activated OOH dissociation on Pt(111) surface and on small Pt clusters. Interestingly, in this work, we found an existence of a \barrierless" OOH dissociation on several Pt-binary and ternary alloy surfaces with Ru and Mo as alloying components: PtRu and PtRuMo. Here, we demonstrate how such reaction proceeds and discuss the role of Ru{O and Mo{O in the spontaneous OOH dissociation in these systems. The reaction energetics of OOH specie is one of the most sought fundamental surface science studies due to its importance in many catalytic and surface reactions such as hydrogen fuel cell. © 2011 The Surface Science Society of Japan.

Arevalo R.L.,Philippine Normal University | Pobre R.F.,De La Salle University - Manila
e-Journal of Surface Science and Nanotechnology | Year: 2011

We investigate the adhesion mechanism of metal atoms (Al, Cu Ag, Au and Pt) on polyethylene terephthalate (PET) using Density Functional Theory (DFT) and cluster models. The structural geometry of the basic unit of PET is optimized then a metal atom is made to approach this structure at different orientations while calculating the total energy of the system under B3LYP functional. Results show that Al atom binds strongly when oriented linear to C=O at a distance of 1.80 A°. Orbital population analysis indicates that the good adhesion of Al at this orientation is due to the interaction of pz orbital of free oxygen in the carbonyl group and py orbital of Al atom. Binding is strongest for Al atom, followed by Pt, Cu, Ag, and Au, in decreasing order of adhesive strength. © 2011 The Surface Science Society of Japan.

Arevalo R.L.,Osaka University | Arevalo R.L.,Philippine Normal University | Escano M.C.S.,Osaka University | Gyenge E.,University of British Columbia | Kasai H.,Osaka University
Surface Science | Year: 2012

The adsorption of borohydride on 3d transition metals (Cr, Mn, Fe, Co, Ni and Cu) was studied using first principles calculations within spin-polarized density functional theory. Magnetic effect on the stability of borohydride is noted. Molecular adsorption is favorable on Co, Ni and Cu, which is characterized by the strong s-d zz hybridization of the adsorbate-substrate states. Dissociated adsorption structure yielding one or two H adatom fragments on the surface is observed for Cr, Mn and Fe. © 2012 Elsevier B.V. All rights reserved.

Arevalo R.L.,Osaka University | Arevalo R.L.,Philippine Normal University | Escano M.C.S.,Osaka University | Kasai H.,Osaka University
Journal of Physical Chemistry C | Year: 2013

Au-3d metal alloys have recently gained interest for use as anode catalysts for direct borohydride fuel cells since these are less expensive than pure Au and exhibit desirable properties for borohydride oxidation. In this paper, a mechanistic study on the electrochemical oxidation of borohydride on Au 3Ni(111) using first principles calculations based on spin-polarized density functional theory is presented. A reaction energy diagram showing the free energies of possible elementary surface-bound species on Au 3Ni(111) as a function of electrode potential is constructed to show the favorable reaction path for a complete eight-electron oxidation of borohydride. As compared to pure Au, the adsorption of borohydride is favorable on Au3Ni(111) at lower potential due to the greater stability of borohydride on this surface, which is attributed to the upshift of the derived antibonding states of the BH4-sp and Au3Ni-d interaction with respect to pure Au. At a potential of -0.44 V vs NHE and T = 300 K, all subsequent elementary reaction steps for the complete oxidation of borohydride are downhill in energy with B(OH)3,ads as the highly favored final adsorbed species. The overall oxidation is limited by the initial adsorption of borohydride on the surface since it requires the highest electrode potential requirement among all electrochemical steps considered. Calculation of the dehydrogenation barrier of borohydride provides significant evidence that a more favorable elementary reaction on Au3Ni(111) as compared to Au(111) also leads to a lower reaction barrier. © 2013 American Chemical Society.

PubMed | De La Salle University - Manila, Philippine Normal University and Mindanao State University - Iligan Institute of Technology
Type: | Journal: Journal of anxiety disorders | Year: 2016

The present study examined the factor structure of six competing posttraumatic stress disorder (PTSD) models based on the recent changes in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) in a sample that, while highly vulnerable to PTSD, very few studies have focused on-Asians, particularly Filipino internally displaced persons (IDPs). In recognition of the role of culture in PTSD factor structure, we also investigated the associations of the factors of the best-fitting model with self-construal. A sample of 460 IDPs in government resettlement communities participated in the study. Results of confirmatory factor analyses revealed the seven-factor hybrid model composed of intrusion, avoidance, negative affect, anhedonia, externalizing behaviors, anxious arousal, and dysphoric arousal as the best-fitting model. Furthermore, it was found that associations between independent self-construal and PTSD factors were higher than that of interdependent self-construal and PTSD factors.

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