IPA Recipients for February 2019

Jonathan V. Caalim and Clarisson Rizzie P. Canlubo
Institute of Mathematics, College of Science
University of the Philippines Diliman

On the Lie algebra associated to S-unitary matrices. Linear Algebra Appl 553 (2018), 167-181. doi.org/10.1016/j.laa.2018.05.010.

This article deals with a natural generalization of unitary groups arising from sesquilinear forms (which are assumed neither Hermitian nor skew-Hermitian). Let S be a square matrix of size n. We say a nonsingular square matrix A of size n is S-unitary if ASA*=S. The set of all S-unitary matrices is a matrix Lie group. It is an interesting problem to classify these Lie groups and determine which of them are Lie isomorphic. An approach to this problem is to look at the associated Lie algebra. We derive a formula for the real dimension of the associated Lie algebra when S is nonsingular and normal. We apply this formula to a class of permutation matrices. Moreover, we prove that the associated Lie algebra is the direct sum of some Lie algebras related to the indefinite unitary groups when S is nonsingular and unitary. This is a joint work with Dr. Yu-ichi Tanaka.

Link to the article: https://www.sciencedirect.com/science/article/pii/S0024379518302416
Impact factor: (2017/2018) 0.972

Minin J. Sinsona and b. Marie Antonette Juinio-Meñez
Marine Science Institute
University of the Philippines Diliman

Effects of sediment enrichment with macroalgae, Sargassum spp., on the behavior, growth, and survival of juvenile sandfish, Holothuria scabra. Aquaculture Reports. 12: 56-63.

Holothuria scabra or sandfish, is a highly-valued sea cucumber species. As such, it is a source of livelihood for coastal dwellers. However, it has been overexploited for international trade and it is currently listed in the IUCN Red List as endangered. Thus, efforts to restore depleted wild stocks are ongoing. Sandfish has been successfully cultured in the hatchery, and the bottleneck now lies in growing out juveniles (~3g) to marketable size (>320 g). One of the major causes of juvenile mortality is predation, and the smaller a juvenile is, the more vulnerable it will be to predators in the wild. Our hypothesis was that juveniles released in microhabitats abundant in food would hasten growth rates, allowing juveniles to reach larger sizes in a shorter amount of time. We tested this hypothesis by enriching sediment with detritus from macroalgae, Sargassum spp., that naturally washes ashore in Bolinao. We found that adding Sargassum spp. detritus to sediment increased microalgal and bacterial abundance, which serve as nutrition for sandfish juveniles. Enrichment with Sargassum also significantly increased growth rates and survival in the field. Results of our study show that sediment enrichment is a viable option in ocean nursery systems for short-term grow out of juveniles to larger sizes of predator refuge within 30 days.

Our paper discusses how enriching sediment with Sargassum spp. detritus significantly hastens the growth of juvenile H. scabra, or sandfish, one of the most commercially important tropical sea cucumbers, by increasing food abundance (i.e., microalgae and bacteria) in the sediment, while relatively increasing burying frequency, and promoting significantly higher survival after release. The results of our study are important in addressing bottlenecks in the grow out of juvenile sandfish to marketable size. Juveniles (~ 3 g) can be protected from predators in sea pens enriched with Sargassum spp. and conditioned to bury and grow to larger sizes (> 20 g) of predator refuge within 30 days.

Link to the article: https://doi.org/10.1016/j.aqrep.2018.09.002
Impact factor: Not yet available

Aurelio A. de los Reyes V and Jose Maria L. Escaner IV
Institute of Mathematics, College of Science
University of the Philippines Diliman

Dengue in the Philippines: model and analysis of parameters affecting Transmission. Journal of Biological Dynamics. 12:1, 894-912. Doi: 10.1080/17513758.2018.1535096

Model diagram depicting the dengue transmission dynamics.

The reported dengue cases by morbidity week and cumulative sum in the Philippines from week 16 to 52 of 2015 and the corresponding model identification.

Dengue is one of the major public health concern in the Philippines which poses a substantial economic burden in the country. In order to understand the qualitative behavior of the disease transmission dynamics, a mathematical model is developed including human and mosquito populations. Incorporated in the model is a healthcare-seeking class depicting the reported dengue cases. This class gives insight on the influence of the number of individuals who get medical attention and/or treatment at the onset of the disease. It further captures the impact of under-reported cases due to passive surveillance. Data on weekly morbidity cases from 2014-2015 obtained from Epidemiology Bureau, Department of Health were used to identify model parameters which are influential in the spread of the disease. These parameters include the mosquito biting rate, transmission probability from mosquito to human, respectively, from human to mosquito, and fraction of individuals who seek healthcare at the onset of the disease. Results of model identification indicate that very few dengue-infected individuals seek treatment and/or there is an inadequate public health facility which eventually lead to unreported cases. Hence, efforts on dengue surveillance should be intensified in order to control dengue virus transmission and better assess the burden estimate of the disease in the country. Further, the model provides information on relative effects of different perturbations in both human and vector population dynamics and could aid in developing more informed decisions on specific control strategies.

Dengue is endemic in the Philippines causing it as one of the major public health concern and thus, poses an economic burden in the country. In this work, a mathematical model is developed to describe the dengue transmission dynamics in the country. Included in the model is a healthcare-seeking class to give insight on the influence of the number of individuals who get medical attention and/or treatment at the onset of the disease. Inclusion of this class captures the impact of under-reported cases due to passive surveillance causing a chronic challenge in endemic countries like the Philippines. Model parameters sensitive to the healthcare-seeking infected class were estimated using the morbidity week (2014-2015) obtained from Epidemiology Bureau, Department of Health. Results of model identification indicate that very few dengue-infected individuals seek treatment and/or there is an inadequate public health facility which eventually lead to unreported cases. Hence, efforts on dengue surveillance should be intensified in order to control dengue virus transmission and better assess the burden estimate of the disease in the country. Further, the model provides information on relative effects of different perturbations in both human and vector population dynamics and could aid in developing more informed decisions on specific control strategies.

Link to the article: https://www.tandfonline.com/doi/full/10.1080/17513758.2018.1535096
Impact factor: Not yet available

Teodora D. Balangcod and Kryssa D. Balangcod
Department of Biology, College of Science
UP Baguio

Plants and Culture:Plant utilization among the local communities in Kabayan, Benguet Province, Philippines. Indian Journal of Traditional Knowledge. 17(4): 609-622

The bole of Benguet pine (Pinus kesiya) can be carved to make a coffin which is placed in a burial rock. This pine coffin can last for many decades

Glochidion sp. is used as a cigarette substitute

The use of plants by the local communities in Kabayan, Benguet has been closely entwined with their cultural practices. From the interviews, the use of plants ranges from food, shelter, clothing, preservation of the dead and mummification, offerings to appease the spirits and many more. Medicinal plants include treatment of skin-related diseases such as wounds, scabies and burns; other illnesses treated using plants are headache, stomach ache, diarrhea, stomach ulcer, anemia, sore throat, and many more.
Plants that are used for ritual activities and paraphernalia include aba (Colocasia esculenta), camote (Ipomoea batatas) and rice wine or tapuy. Rono (Miscanthus sp.) and banana (Musa paradisiaca) are versatile plants as these have varied uses, as ritual paraphernalia and in agriculture. Tapuy, made from rice varieties, is an inevitable component during festivities and served on a coconut shell. The sweet and savory taste of the tapuy, can make anyone brave and utter anything, which add up to the merry making. Tobacco with tapuy are offered to appease the gods and spirits so they will not inflict pain over the village. Acorus calamus, an aromatic plant, is pinned on one’s clothes to drive away evil spirits. The shoot of Cyathea contaminans, a giant tree fern, is used as a substitute for a human head and offered to bargain for a very sick person to get well. In the old times, a human head, may be taken from a neighboring village member. Other uses of plants include for construction, ornamentals, clothing, cigarette and many others.

Ethnobotanical knowledge in the Cordillera region is not many yet the region is a repository of rich cultural diversity and diverse flora and fauna. This piece of literature is a great contribution to the dearth of publications about the ethnobotanical knowledge. It also hopes to provide baseline information on the various plant uses especially on medicinal plants which the area is very rich. Conversely, the knowledge on medicinal plants can also initiate efforts on drug discovery.

Link to the article: http://nopr.niscair.res.in/bitstream/123456789/45073/1/IJTK%2017%284%29%20609-622.pdf
Impact factor: (2017/2018) 1.061

Butch G. Bataller
Department of Chemical Engineering, College of Engineering and Agro-Industrial Technology
UP Los Baños

A rapid and non-destructive method for quantifying biomolecules in Spirulina platensis via Fourier transform infrared – Attenuated total reflectance spectroscopy. Algal Research, Vol. 32, pp. 341-352.

Actual vs. predicted plot of PLS-regression model for (a) protein, (b) carbohydrate, and (c) lipid on model cell spectra for Spirulina using NIPALS algorithm and leave-one-out cross validation method

Scatter plot showing mean and standard deviation of algal composition determined by conventional biochemical methods and multipoint and PLS-regression for (a) protein, (b) carbohydrate, and (c) lipid; where BFA = Macro-Bradford Assay, PSA = Phenol-sulfuric acid method, BG = Bigogno method, MP = Multipoint regression, and PLS = PLS-regression

This study aimed to develop a method that rapidly quantifies protein, carbohydrates and lipid content of the algae, Spirulina platensis, through the use of Fourier Transform Infrared (FTIR) spectroscopy and partial least square regression. In FTIR, infrared light is irradiated to the sample to cause vibrations in the covalent bonds of the target molecules in the sample. The target molecules are detected, as a plot of absorbance or transmittance, at characteristic wavelengths. Higher concentrations of the target biomolecule will have higher absorbance. Therefore, a regression model can be made at different concentrations of the target molecule. However, for an FTIR data that usually contains numerous, noisy and collinear variables, Partial least square (PLS) regression is most applicable. In this study, model spectra of Spirulina biomass were made from the individual spectra of glucose (carbohydrate), bovine serum albumin (protein) and glycerol tripalmitate (lipid) standards at various concentrations. Then, PLS-regression models were made from the model spectra of the biomass for each biomolecule at their characteristic wavelengths. These regression models were tested and validated by comparing the predicted results to the conventional analytical methods for determining protein, carbohydrate, and lipid content. It was found that the PLS-regression models were statistically similar to the results of the conventional methods. Thus, FTIR spectroscopy coupled with PLS-regression technique can replace conventional methods that are usually time-consuming and destructive to algal cells.

This research work developed a novel analytical method in quantifying biomolecules such as protein, carbohydrates, and lipids in Spirulina biomass through the use of chemometric (partial least square regression) technique and FTIR spectroscopy. This method is fast as results can be obtained in a few minutes. Tedious sample preparation and extraction of the target analyte are eliminated. The method is also non-destructive to the cells since high temperature and use of toxic solvents for extraction are not needed. Losses from sample preparation and extraction steps are also prevented since the method can determine the biomolecule content directly from the whole-cell biomass. This method can be used for instantaneous monitoring of biomolecule production of the algal cells. This method is highly species specific and has not yet been done on Spirulina platensis.

Link to the article: https://doi.org/10.1016/j.algal.2018.04.023
Impact Factor: Not yet available

Merdelyn T. Caasi-Lit, Artemio A. Salazar, Jefferson F. Paril, Ayn Kristina M. Beltran, Maria Alma B. Sanchez and Bryan V. Novio
Institute of Plant Breeding, College of Agriculture and Food Science
UP Los Baños

Sources of resistance to Asian corn borer, [Ostrinia furnacalis (Guenee)] in Philippine’s maize varieties. Society for the Advancement of Breeding Research in Asia and Oceania (SABRAO) Journal of Breeding and Genetics, Volume 50 (3), 254-269

Field evaluation trial of Philippine traditional maize for Asian corn borer resistance

ACB Life Cycle

Maize in the Philippines is an important cash crop second to rice. Several insect pests are main constraints in production. One of the major insect pests of corn is the Asian corn borer (ACB), Ostrinia furnacalis (Guenee). This pest is able to consume all parts of corn thus at very high level of infestation, farmer’s harvest is greatly decreased. With this, different control methods have been developed to manage these pests. One is the use of insecticides, however most active chemical principles pose hazard to farmer’s health and even the consumers. Biological and cultural methods such as use of Trichogramma wasps and detasselling are also useful but need to be integrated in an Integrated Pest Management (IPM) program to ensure effective control. One of the components of IPM is the use of resistant varieties to insect pests. Deployment of varieties resistant to ACB can serve as environment-friendly and cheaper control method. These varieties can serve as primary line of farmer’s defense against ACB attack. Traditional corn in the country has not yet been utilized to target sources of resistance against ACB. These varieties have been cultivated in various corn growing areas and thrived despite emergence of biotic stresses. A keyfinding of this study is that selected traditional varieties showed moderate to high levels of resistance against ACB through screening tests conducted in the laboratory and field. The resistant materials can be used as donor parents for breeding Philippine’s traditional corn for improved ACB resistance.

There has been no breeding program for resistance to Asian corn borer (ACB) a major insect pest of corn in the country, where many areas still mainly utilize native or traditional corn. Genetic variability among these traditional varieties can be the main reason why these landraces still survive in the Philippines soil despite the various existing and emerging abiotic and biotic stresses. With rich genetic diversity of native corn populations or accessions in the tropics, sources of resistance to ACB may be available.

Link to the article: http://sabraojournal.org/wp-content/uploads/2018/09/SABRAO-J-Breed-Genet-50-3-254-269-CAASI-LIT.pdf
Impact Factor: Not yet available

Marjorie Anne A. Layosa, Liezl M. Atienza and Angelina DR. Felix
Institute of Human Nutrition and Food, College of Human Ecology
UP Los Baños

Cadmium and Lead Contents and Potential Health Risk of Brown Rice (NSIC Rc222 Tubigan 18) Cultivated in Selected Provinces in the Philippines. Malaysian Journal of Nutrition, 24 (2): 287-292, 2018

White rice is a big part of the Filipino diet; however, brown rice is being promoted because it is a healthier option as compared to white rice. Brown rice is less milled hence it has more tendency to retain its nutrients, as well as the contamination absorbed from air, water and soil such as heavy metals cadmium (Cd) and lead (Pb). With the deteriorating environmental quality, human exposures to heavy metals have increased dramatically through their diet.
We investigated the potential health risk of brown rice from Nueva Ecija, Ilo-ilo and Bukidnon with the assumption that Filipinos will consume it as part of their regular diet as a result of its promotion. Analyses showed that Cd content is within the safe limit but Pb content in all provinces exceeds the allowable limit. Nonetheless, calculating the potential hazard of consuming the brown rice in the long run shows that it is still safe and has low probability for carcinogenic effects. However, there are other heavy metals possibly present and may contaminate brown rice such as mercury (Hg) that it is worth investigating. Also, this study shows the importance of the entire pathways of the food systems from production to food utilization in the totality of health and nutrition.

The research demonstrates that promotion of healthier food options, such as brown rice as part of the Filipino diet, should also ensure the quality and safety from environmental effluents such as heavy metals cadmium (Cd) and lead (Pb). The study is significant as it showed that lead content among sampled brown rice exceeds the allowable limit set by FAO/WHO Food Standards Program. Fortunately, the detected amount is still safe for long-term consumption. Nonetheless, the study shows the importance of environmental quality in safe and healthy food production and consequently, promotion. 

Link to the article: http://nutriweb.org.my/mjn/publication/24-2/n.pdf
Impact Factor: Not yet available

Allan Abraham B. Padama
Institute of Mathematical Sciences and Physics, College of Arts and Sciences
UP Los Baños

Adsorption of H on Cs/W(110): Impact of H on the Stability of Cs on the Surface. e-Journal of Surface Science and Nanotechnology, 16 (2018) 391-395

This study investigated the impact and influence of Hydrogen (H) on the stability of Cesium (Cs) atoms on Tungsten (W) surface. Cs finds importance in lowering the work function of metal surfaces. Low work function materials are used to produce negative hydrogen ions which are used as sources in fusion research and in high energy accelerators. Despite the effectiveness of Cs in such application, experimentalists observed that Cs atoms become unstable during actual operations. The atoms are sputtered out from the surface which makes the process inefficient and usually damages the system. This phenomenon is attributed to the presence of impurities. In this regard, we investigated the influence of H to the Cs atoms and analyzed the interactions in the atomic scale. We found that adsorption of H weakens the adsorption of Cs on W surface. It is therefore necessary to reconsider current designs of Cs/metal systems to further enhance their stability without affecting the desired performance. The electronic properties presented in our work could serve as benchmark for future designs of the systems.

This work is a computational/theoretical based research that aimed to understand the co-adsorption of hydrogen and cesium on metal surface in the atomic-scale level. Cesiated metal systems are used as electrodes to produce negative hydrogen ions which are essential in fusion research and in high energy accelerators. This study provides explanation on the experimentally observed unstable behavior of Cs on surfaces in the presence of other adsorbates. While previous studies attributed the phenomenon to the presence of ionized particles and to the plasma environment, this present work revealed that even the hydrogen itself contributes to the weakening of Cs adsorption on the metal surface. The analysis on the electronic and geometric properties of the systems will serve as guide in future designs to stabilize Cesium atoms in metal surfaces.

Link to the article: https://doi.org/10.1380/ejssnt.2018.391
Impact Factor: Not yet available

Menandro N. Acda
Department of Forest Products and Paper Science, College of Forestry and Natural Resources
UP Los Baños

Tobacco (Nicotiana tabacum) stalk particles as additive in urea formaldehyde bonded plywood. Journal of Adhesion Science and Technology DOI: 10.1080/01694243.2018.1509501

Tobacco stalks harvested from Pangasinan

Adhesive mixed with tobacco stalk particles used to glue veneers into plywood

Plywood specimens bonded with glue with tobacco particles to tested for strength properties

The study investigated the use of tobacco (Nicotiana tabacum L) stalk particles as additive of adhesive formulation used for plywood manufacture. The effect of varying amount of tobacco stalk particles on adhesive working properties, shear strength and wood failure of 3-ply plywood was investigated. Adhesive mix containing urea formaldehyde resin with tobacco stalk particles up to 8% by mass blended very well and remained stable for atleast 1 hour. An increase or no significant effect on shear strength and wood failure up to 8% tobacco stalk loading was observed compared to plywood that used a commercial glue formulation. Based on shear strength and wood failure, panels containing 4–8% tobacco stalk particles would pass the requirements of ISO 12466-2. Examination of adhesive penetration and plywood strength suggest that tobacco particles could function as both filler and extender. Tobacco stalk particles offer an environmentally friendly, low cost, strong and non-abrasive alternative to conventional fibers used in plywood production.

Tobacco (Nicotiana spp.) is one of the most valuable agricultural products in the world. It is grown in over 125 countries on over 4 million hectares of land. In the Philippines, over 37,000 hectares of land are planted with tobacco with production value of over 4.6 billion pesos. After the leaves are harvested, the tobacco stalks are incorporated in the soil or burned in the field. However, presence of nicotine in waste tobacco stalks pose increasing solid waste disposal and pollution problems in many countries. Considering the insecticidal properties of nicotine in tobacco stalk, an attractive utilization of this waste material is filler in the glue formulation used in plywood manufacture. Plywood is a major building material in the Philippines used as paneling, table tops, cabinets, door skin, furniture components, etc. Fillers are inert material used to improve glue properties. Incorporation of ground tobacco stalk in the adhesive formulation used to manufacture plywood could render the panel toxic or repellent to wood boring insects such as termites and powder post beetles (“bukbok”). Repellent effects of tobacco stalks against termites had already been demonstrated when used as component of particleboard. The potential use of waste tobacco stalk as raw material in plywood manufacture could benefit the Philippine wood industry by providing plywood panels with increased termite resistant properties. In addition, the proposed utilization of tobacco stalk could alleviate its waste disposal problems, pollution and efficient utilization of this biomass material.

Links to the article:
Impact factor: Impact Factor: (2017/2018) 1.039

 Arnold R. Salvacion
Department of Community and Environmental Resource Planning, College of Human Ecology
UP Los Baños

Spatial pattern and determinants of village level poverty in Marinduque Island, Philippines. GeoJournal. https://doi.org/10.1007/s10708-018-9944-6

This study explores the spatial pattern and determinant of poverty at the village level in the province of Marinduque, Philippines. Based on the results, poverty in the province varies spatially. Also, village characteristics such as slope, annual rainfall, population growth rate, distance to town centers, and distance to ports were found to have significant effect on village level poverty incidence.

The study explore the spatial pattern and potential determinants of poverty in the province of Marinduque, Philippines. Resutls from this study can be used by the province to address its poverty problem. Also, the methodology of this study can be also applied to other poverty-stricken province in the country.

Link to the article: https://link.springer.com/article/10.1007/s10708-018-9944-6
Impact Factor: Not yet available

Remil L. Galay
Department of Veterinary Paraclinical Sciences, College of Veterinary Medicine
UP Los Baños

Characterization and expression analysis of a newly identified glutathione S-transferase of the hard tick Haemaphysalis longicornis during blood feeding. Parasites and Vectors, 11:91

Ticks suck large amounts of blood from their host, which exposes them to harmful substances that can result to oxidative stress and induce cellular damage. To prevent that, ticks have antioxidant molecules. In this study, a new glutathione s-transferase (GST), HlGST2, was identified and characterized together with the previously identified GST, HlGST. Recombinant GSTs prepared from Escherichia coli were analyzed for enzymatic activity. The gene and protein expressions of GSTs in different organs and developmental stages of the tick during blood feeding were analyzed. The localization of GSTs in different organs were also examined through immunofluorescent antibody technique. Results showed that recombinant GSTs exhibit GST activity. High GST gene and protein expression were observed in the tick midgut, upregulated as blood feeding progressed, suggesting its protective role against promoters of oxidative stress that are acquired from the tick’s blood meal. The high expression of GSTs in the hemocytes of the ticks also suggest their function in tick immunity. Taken together, the results of the study indicate the importance of GSTs in tick physiology.

A new glutathione s-transferase, an antioxidant, was identified in the tick Haemaphysalis longicornis. This molecule has been found to be crucial to tick biology. Understanding of the different aspects of tick biology is important in design of tick control strategies.

Link to the article: https://parasitesandvectors.biomedcentral.com/articles/10.1186/s13071-018-2667-1
Impact factor: Not yet available