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Faculty Publication (2017)

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1. Buhian, W. P. C., Rubio, R. O., & Martin-Puzon, J. J. (2017). Chromatographic fingerprinting and free-radical scavenging activity of ethanol extracts of Muntingia calabura L. leaves and stems. Asian Pacific Journal of Tropical Biomedicine, 7(2), Pages 139–143. more

Abstract:

Objective

To determine the thin-layer chromatography (TLC) fingerprint profiles and to evaluate the in vitro antioxidant activity of ethanol extracts of Muntingia calabura (M. calabura) leaves and stems.

Methods

The leaves and stems were extracted using ethanol as solvent. The TLC separation of the phytochemical constituents of the leaf and ethanol extracts was carried out in ethyl acetate: n-hexane and chloroform: ethyl acetate mobile phase systems. Distinct spots were visualized under visible light, UV 254 nm, UV 366 nm and after spraying with vanillin-sulfuric acid. The 2,2-diphenyl-1-picrylhydrazyl free-radical scavenging assay was used to evaluate the antioxidant activity of the extracts.

Results

Both the leaf and stem ethanol extracts at 4 mg/mL exhibited 2,2-diphenyl-1-picrylhydrazyl inhibition of more than 90%, relative to gallic acid. The results of TLC showed that the degree of resolution between the constituent spots was comparable between the two mobile phase systems using the different visualization wavelengths. Under the 254 nm visualization, few spots were observed in leaf and stem extracts. Visualization at 366 nm yielded the greatest number of observable spots of various colors in both leaf and stem extracts. More spots were visualized upon post-derivatization with vanillin-sulfuric acid in the TLC chromatograms using chloroform: ethyl acetate mobile phase, compared to those in ethyl acetate: n-hexane mobile phase.

Conclusions

M. calabura exhibited very high antioxidant activity in its leaves and stems ethanol extracts, both of which are used in traditional medicine. The TLC results demonstrated the presence of diverse secondary metabolites in the leaf and stem ethanol extracts, indicating that the antioxidant activity, including other bioactivities may be attributed to these phytochemical constituents. This paper has reported for the first time the TLC fingerprinting of M. calabura using visible light, UV 254 nm, UV 366 and post-derivatization with vanillin-spray to visualize separate spots on TLC plates.

 

2. Dumilag, R. V., & Aguinaldo, Z.-Z. A. (2017). Genetic differentiation and distribution of Pyropia acanthophora (Bangiales, Rhodophyta) in the Philippines. European Journal of Phycology, 0(0), Pages 1–12. more

Abstract:

Pyropia acanthophorais a foliose Bangiales with widely known endemic populations in Indo-Pacific region. This alga has expanded its range recently as a consequence of introduction. In an attempt to explore the genetic diversity of Py. acanthophora within the Philippines and the impact of the introduction of the species from elsewhere, an examination of molecular differentiation and distribution was undertaken using the mitochondrial COI-5P and plastid rbcL gene sequences. The results revealed that the populations of Py. acanthophora in the Philippines exhibited high haplotypic and genetic diversities, and were found to be distinct from those previously reported as conspecific populations found in Taiwan, India, Japan, Hawaii, and from those introduced populations from Brazil. The network analyses as inferred fromrbcL and from the combined COI-5P and rbcL genes showed evidence that the Philippine populations of Py. acanthophora exhibited a chaotic patchiness pattern characterized by a population with highly site-exclusive haplotypes, wide genet ic variability and lack of local geographic patterns. The distribution of Py. acanthophora within the Philippines was also found to be greater than what was previously known, ranging from the extreme northwest to extreme northeast mainland Luzon coasts, including Camiguin Is., Cagayan. Understanding the genetic diversity and distribution of Py. acanthophora in the Philippines provides valuable information in relation to the conservation and effective resource management of native populations of Py. acanthophora in the tropical Asian region.

 

IM

1. Akiyama, S., & Caalim, J. (2017). Invariant Measure of Rotational Beta Expansion and Tarski’s Plank Problem. Discrete & Computational Geometry, 57(2), Pages 357–370.

2. Arceo, C. P. P., Jose, E. C., Lao, A. R., & Mendoza, E. R. (2017). Reaction networks and kinetics of biochemical systems. Mathematical Biosciences, 283, Pages 13–29.

3. John, R., Cruz, D., Merino, D. I., & Paras, A. T. (2017). Every 2 n -by-2 n complex matrix is a sum of three symplectic matrices. Linear Algebra and Its Applications, 517, Pages 199–206.

4. Loquias, M. J. C., Mkaouar, M., Scheicher, K., & Thuswaldner, J. M. (2017). Rational digit systems over finite fields and Christol’s Theorem. Journal of Number Theory, 171, Pages 358–390. 

 

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1. Da-Anoy, J. P., Villanueva, R. D., Cabaitan, P. C., & Conaco, C. (2017). Effects of coral extracts on survivorship, swimming behavior, and settlement of Pocillopora damicornis larvae. Journal of Experimental Marine Biology and Ecology, 486, Pages 93–97.

2. Dumilag, R. V., & Aguinaldo, Z.-Z. A. (2017). Genetic differentiation and distribution of Pyropia acanthophora (Bangiales, Rhodophyta) in the Philippines. European Journal of Phycology, 0(0), Pages 1–12.

3. Noblezada, M. M., Miyamoto, H., Campos, W. L., Yusoff, F. M., & Nishida, S. (2017). Phylogeography of the planktonic shrimp Lucifer hanseni Nobili 1905 in the Indo-Malayan Archipelago. Journal of the Marine Biological Association of the United Kingdom, 97(1), Pages 129–140.

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1. Rosete, M.M., Zosa, M.H., & Sarmago, R.V. (2017). Effect of Potassium Chloride as a Supporting Electrolyte on the Dispersion Towards the Fabrication of Films by Electrophoretic Deposition of Bi2Sr2CaCu2O8 in Ethanol. Journal of Superconductivity and Novel Magnetism, Pages 1-6more

Abstract:

Bi2Sr2CaCu2O8 (Bi-2212) powder was fabricated using solid state reaction method. The suspensions were prepared containing finely ground Bi-2212 powder with and without potassium chloride (KCl) addition. Settling experiments and measurements of zeta potential, particle size distribution, and electrophoretic mobility were performed to determine the optimal concentration of the supporting electrolyte. Bi-2212 suspensions were used in electrophoretic deposition (EPD), and the films were heat treated. The results showed that the optimal concentration of KCl is 5.21 wt %. The zeta potential at this concentration is highest at about 31.10 mV, the settling velocity is lowest ∼3.84 mm/min, and the particle size is smallest (∼450 nm), which indicate that the dispersion is better due to the reduction of intermolecular attraction. The effects of KCl as a flux were observed in the microstructure and superconducting properties of Bi-2212 film. The smoothest surface morphology, high c-axis orientation, and highest critical temperature (Tc)-onset of 84.73 K were obtained from the film prepared with optimized Bi-2212 suspension.

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1. Knittel, U., Walia, M., Suzuki, S., Dimalanta, C. B., Tamayo, R., Yang, T. F., & Yumul, G. P. (2017). Diverse protolith ages for the Mindoro and Romblon Metamorphics (Philippines): Evidence from single zircon U-Pb dating. Island Arc, 26(1), e12160.more

Abstract:

Within the north-eastern part of the Palawan Continental Terrane, which forms the south-western part of the Philippine archipelago, several metamorphic complexes are exposed that are considered to be rifted parts of the Asian margin in South-East China. The protolith age(s) and correlations of these complexes are contentious. The largest metamorphic complex of the Palawan Continental Terrane comprises the Mindoro Metamorphics. The north-eastern part of this metamorphic complex has recently been found to be composed of protoliths of Late Carboniferous to Late Permian protolith age. However, meta-sediments exposed at the westernmost tip and close to the southern boundary of the exposure of the Mindoro Metamorphics contain detrital zircons and with U–Pb ages, determined by LA–ICP–MS, in the range 22–56 Ma. In addition, zircons as young as 112 Ma were found in a sample of the Romblon Metamorphics in Tablas. As the youngest detrital zircons provide an upper age limit for the time of deposition in meta-sediments, these results suggest that the Mindoro and Romblon Metamorphics comprise protoliths of variable age: Late Carboniferous to Late Permian in NE Mindoro; Eocene or later in NW Mindoro; Miocene at the southern margin of the Mindoro metamorphics; and Cretaceous or later on Tablas. The presence of non-metamorphic sediments of Late Eocene to Early Oligocene age in Mindoro (Lasala Formation), which are older than the youngest metasediments, suggests that metamorphism of the young meta-sediments of Mindoro is the result of the collision of the Palawan Continental terrane with the Philippine Mobile Belt in Late Miocene. Similarities of the age spectra of zircons from the Eocene to Miocene metamorphics with the Eocene to Early Miocene Lasala Formation suggest that the protoliths of the young metamorphics may be equivalents of the Lasala Formation or were recycled from the Lasala Formation.

2. Li, H., Sun, H.-S., Wu, J.-H., Evans, N. J., Xi, X.-S., Peng, N.-L., … Gabo-Ratio, J. A. S. (2017). Re–Os and U–Pb geochronology of the Shazigou Mo polymetallic ore field, Inner Mongolia: Implications for Permian–Triassic mineralization at the northern margin of the North China Craton. Ore Geology Reviews, 83, Pages 287–299.more

Abstract:

The recently discovered polymetallic Shazigou Mo–W–Pb–Zn ore field is located at the northern margin of the North China Craton. This integrated metallogenic system is comprised of quartz vein mineralization in three deposits: Shazigou Mo–W, Jindouzishan Pb–Zn and Mantougou Pb–Zn. The total reserves are estimated to be 50 kt Mo, 626 t WO3, 244 kt Pb and 150 kt Zn. Molybdenite Re–Os dating of five quartz vein-type ores yielded a mean model age of 243.8 ± 1.6 Ma (MSWD = 0.81) and hydrothermal zircons yielded a concordant U–Pb age of 245 ± 2.6 Ma (MSWD = 0.65). These results suggest that the mineralization was formed in the early Triassic and could be related to Paleo-Asian Ocean subduction. Microthermometry and quartz fluid inclusion compositions indicate that fluids related to the Mo–W mineralization were mainly derived from magmatic sources and precipitated under relatively high temperature (280–340 °C) and salinity conditions (6–9 wt% NaCl equiv.), whereas subsequent Pb–Zn mineralization-related fluids may have been modified by metamorphic and meteoric waters. The discovery of the Shazigou ore field suggests conditions may be favourable for more extensive mineralization in the western Xilamulun Mo metallogenic belt at the northern margin of the North China Craton.

3. Zuluaga, M. C., Norini, G., Lima, A., Albanese, S., David, C. P., & De Vivo, B. (2017). Stream sediment geochemical mapping of the Mount Pinatubo-Dizon Mine area, the Philippines: Implications for mineral exploration and environmental risk. Journal of Geochemical Exploration, 175, Pages 18–35. more

Abstract:

Stream sediments transport elements that are mobilized from adjacent slopes, representing the composition of the upstream watersheds. Thus, the analysis of the stream sediments allows depicting the spatial distribution of geochemical anomalies at the watershed level. In this study, 39 samples of stream sediments were collected in the Zambales Province, in the Philippines, characterized by the presence of the Mount Pinatubo volcano, the abandoned Cu Dizon Mine, small-mining of black sand, agriculture of rice, animal breeding, and fishing. Each sample was digested in aqua regia and was analyzed by ICP-MS to detect the content of 53 elements. This study is focused on elements with an environmental impact or associated to mineralization/ore occurring in the area. Background values for these elements have been evaluated by cumulative frequency curve to identify the occurrence of geochemical anomalies of geogenic or anthropogenic origin, mainly associated to the mining activity. Factor analysis, performed on normalized data with Additive Log Ratio transformation (ALR), allowed identifying three geochemical data associations, and a Geographic Information System (GIS) has been used to define the spatial distribution of the anomalies at the watersheds level. The GIS procedure assigns the value of the element concentration in the sampling location to the upstream watershed by hydrologic analysis of a Digital Elevation Model (DEM) of the study area. The main result of this study is a new type of geochemical mapping of the of the Mount Pinatubo-Dizon Mine area, representing a first approach to the definition of the environmental risk and the assessment of potential mineral resources.

nimbb

1. Zumaraga, M. P., Medina, P. J., Recto, J. M., Abrahan, L., Azurin, E., Tanchoco, C. C., … Palmes-Saloma, C. (2017). Targeted next generation sequencing of the entire vitamin D receptor gene reveals polymorphisms correlated with vitamin D deficiency among older Filipino women with and without fragility fracture. The Journal of Nutritional Biochemistry, 41, Pages 98–108.more

Abstract:

This study aimed to discover genetic variants in the entire 101 kB vitamin D receptor (VDR) gene for vitamin D deficiency in a group of postmenopausal Filipino women using targeted next generation sequencing (TNGS) approach in a case–control study design. A total of 50 women with and without osteoporotic fracture seen at the Philippine Orthopedic Center were included. Blood samples were collected for determination of serum vitamin D, calcium, phosphorus, glucose, blood urea nitrogen, creatinine, aspartate aminotransferase, alanine aminotransferase and as primary source for targeted VDR gene sequencing using the Ion Torrent Personal Genome Machine. The variant calling was based on the GATK best practice workflow and annotated using Annovar tool. A total of 1496 unique variants in the whole 101-kb VDR gene were identified. Novel sequence variations not registered in the dbSNP database were found among cases and controls at a rate of 23.1% and 16.6% of total discovered variants, respectively. One disease-associated enhancer showed statistically significant association to low serum 25-hydroxy vitamin D levels (Pearson chi-square P-value=0.009). The transcription factor binding site prediction program PROMO predicted the disruption of three transcription factor binding sites in this enhancer region. These findings show the power of TNGS in identifying sequence variations in a very large gene and the surprising results obtained in this study greatly expand the catalog of known VDR sequence variants that may represent an important clue in the emergence of vitamin D deficiency. Such information will also provide the additional guidance necessary toward a personalized nutritional advice to reach sufficient vitamin D status.

nip 

1. Caballar, R., Butanas, B., Villegas, B., & Estrella, M. (2017). Dissipation induced quantum transport on a finite one-dimensional lattice.

2. de los Reyes, A., Prieto, E. A. P., Omambac, K., Porquez, J., Lopez, L., Gonzales, K. C., … Salvador, A. A. (2017). Terahertz emission characteristics of GaMnAs dilute magnetic semiconductor under 650 mT external magnetic field. Current Applied Physics, 17(4), Pages 522–526.

3. Galapon, E. A. (2017). The problem of missing terms in term by term integration involving divergent integrals. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 473(2197).

4. Pang, J. C. S., & Monterola, C. P. (2017). Dendritic growth model of multilevel marketing. Communications in Nonlinear Science and Numerical Simulation, 43, Pages 100–110.more

Abstract:

Biologically inspired dendritic network growth is utilized to model the evolving connections of a multilevel marketing (MLM) enterprise. Starting from agents at random spatial locations, a network is formed by minimizing a distance cost function controlled by a parameter, termed the balancing factor bf, that weighs the wiring and the path length costs of connection. The paradigm is compared to an actual MLM membership data and is shown to be successful in statistically capturing the membership distribution, better than the previously reported agent based preferential attachment or analytic branching process models. Moreover, it recovers the known empirical statistics of previously studied MLM, specifically: (i) a membership distribution characterized by the existence of peak levels indicating limited growth, and (ii) an income distribution obeying the 80−20 Pareto principle. Extensive types of income distributions from uniform to Pareto to a “winner-take-all” kind are also modeled by varying bf. Finally, the robustness of our dendritic growth paradigm to random agent removals is explored and its implications to MLM income distributions are discussed. 

5. Rosete, M. M., Zosa, M. H., & Sarmago, R. V. (2017). Effect of Potassium Chloride as a Supporting Electrolyte on the Dispersion Towards the Fabrication of Films by Electrophoretic Deposition of Bi2Sr2CaCu2 O 8 in Ethanol. Journal of Superconductivity and Novel Magnetism, Pages 3–8.more

Abstract:

Bi2Sr2CaCu2O8 (Bi-2212) powder was fabricated using solid state reaction method. The suspensions were prepared containing finely ground Bi-2212 powder with and without potassium chloride (KCl) addition. Settling experiments and measurements of zeta potential, particle size distribution, and electrophoretic mobility were performed to determine the optimal concentration of the supporting electrolyte. Bi-2212 suspensions were used in electrophoretic deposition (EPD), and the films were heat treated. The results showed that the optimal concentration of KCl is 5.21 wt %. The zeta potential at this concentration is highest at about 31.10 mV, the settling velocity is lowest 3.84 mm/min, and the particle size is smallest (450 nm), which indicate that the dispersion is better due to the reduction of intermolecular attraction. The effects of KCl as a flux were observed in the microstructure and superconducting properties of Bi-2212 film. The smoothest surface morphology, high c-axis orientation, and highest critical temperature (Tc)-onset of 84.73 K were obtained from the film prepared with optimized Bi-2212 suspension. 

6. Tingzon, P., Lopez, L., Oliver, N., Cabello, N., Cafe, A., De Los Reyes, A., … Somintac, A. (2017). Terahertz emission and photoluminescence of Silicon Nanowires electrolessly etched on the surface of Silicon (100), (110), and (111) substrates for photovoltaic cell applications. Photonics and Nanostructures - Fundamentals and Applications, 24, Pages 1–6.

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1.Buhian, W. P. C., Rubio, R. O., & Martin-Puzon, J. J. (2017). Chromatographic fingerprinting and free-radical scavenging activity of ethanol extracts of Muntingia calabura L. leaves and stems. Asian Pacific Journal of Tropical Biomedicine, 7(2), Pages 139–143.