National Research Council of the Philippines

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National Research Council of the Philippines

the Philippines, Philippines
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Torres R.C.,Industrial Technology Development Institute | Torres R.C.,National Research Council of the Philippines | Garbo A.G.,Industrial Technology Development Institute | Walde R.Z.M.L.,National Research Council of the Philippines
Parasitology Research | Year: 2015

Recent studies regarding the harmful effects of synthetic larvicides initiated the need to investigate for unconventional measures that are environmentally safe and target-specific against Aedes aegypti larvae. Thus, the main objectives of the study are to evaluate the larvicidal toxicity of the solvent fractions of Anacardium occidentale shell wastes against the third and fourth instar larvae of A. aegypti and to compare the results with the commercial larvicide product. The shell wastes were extracted with 95 % EtOH followed by polarity-based fractionation. The fractions were tested for larvicidal activity according to the World Health Organization bioassay method. These were then characterized by quantitative thin-layer chromatographic (TLC) fingerprinting. The hexane fraction gave the strongest activity among the fractions with an LC50 of 4.01 mg/L and LC90 of 11.29 mg/L highly comparable to the commercial larvicide, which exhibited an LC50 of 1.71 mg/L and LC90 of 8.41 mg/L. The dichloromethane fraction exhibited 9.70 mg/L LC50 and 18.44 mg/L LC90. The remarkable toxicity effects exhibited by these fractions indicate their potential to provide core structures from which sustainable and environmentally safe plant-based larvicidal agents can be synthesized. © 2015, Springer-Verlag Berlin Heidelberg.


Villagracia A.R.C.,De La Salle University - Manila | Villagracia A.R.C.,National Research Council of the Philippines | Mayol A.P.,De La Salle University - Manila | Ubando A.T.,De La Salle University - Manila | And 11 more authors.
Clean Technologies and Environmental Policy | Year: 2016

Algal biofuels serve as a promising alternative energy source for liquid fuels. However, one of the bottlenecks in the conversion of microalgae to biofuels is the drying process. A moisture content of at most 10 % is desired for algal biomass prior to oil extraction to maximise biofuel yield. Conventional means of drying results to longer drying time and uneven drying of algal biomass. This study investigated the drying characteristics of microwave for microalgae (Chlorella vulgaris). Three microwave intensity levels (300, 600, and 900 W) were considered to dry 10, 20, and 30 of algal mass. Page model gave a better fit on the moisture ratio with time of microwave drying than the exponential model. Furthermore, the specific energy requirement was computed, and a relationship was found between moisture ratio with power and mass. Fourier transform infrared spectroscopy results showed significant reduction of infrared signal intensities of the functional groups present in the algae after drying at higher microwave power level. It was concluded that the 20 W/g microwave drying setting gave a lower specific energy requirement with good quality of remaining high lipid content qualitatively. Furthermore, it was recommended to use gas chromatography mass spectroscopy to further quantify the algal lipids and other functional groups. © 2016 Springer-Verlag Berlin Heidelberg


Torres R.C.,Industrial Technology Development Institute | Torres R.C.,National Research Council of the Philippines | Garbo A.G.,Industrial Technology Development Institute | Walde R.Z.M.L.,National Research Council of the Philippines
Asian Pacific Journal of Tropical Medicine | Year: 2014

Objective: To evaluate the toxicity of the ethanol and hexane extracts of the different parts of Persea americana Mill. (P. americana) toward third and fourth instars larvae of Aedes aegypti (Ae. aegypti) and to characterize the ethanol extract by qualitative phytochemical analysis. Methods: The seeds, peels and pulp of P. americana were processed for crude extraction using 95% ethanol and n-hexane. Crude extracts were bio-assayed for larvicidal activity against Ae. aegypti following the World Health Organization standard bioassay method. The mortality was observed at 24 h and 48 h after treatment and data were subjected to probit analysis to determine lethal concentrations (LC50 and LC90). The ethanol extract was characterized by phytochemical analysis. Results: Both the hexane and ethanol extracts from the different parts of P. americana exhibited evidence of larvicidal toxicity. The hexane extract from the seeds exhibited the highest toxicity with LC50 and LC90 values of 9.82 mg/L and 22.19 mg/L, respectively, while the ethanol seed extract exhibited LC50 of 16.48 mg/L and LC90 45.77 mg/L, respectively. This was closely followed by the ethanol extract of the peels with an LC50 of 10.35 mg/L and LC90 of 26.29 mg/L. The pulp extracted with ethanol also yielded great larvicidal toxicity with LC50 of 21.32 mg/L and LC90 of 59.45 mg/L. Results of the phytochemical analysis of the ethanol seed extract indicated presence of alkaloids, tannins, saponins, unsaturated steroids and triterpenoids, flavonoids (leucoanthocyanins), fats and oils. Conclusions: Both the hexane and ethanol extracts of P. americana showed promising potential as an alternative source of a more sustainable, non-toxic and environmentally friendly solution for the control of dengue vector, Ae. aegypti. © 2014 Hainan Medical College.


Mananghaya M.,De La Salle University - Manila | Mananghaya M.,National Research Council of the Philippines
International Journal of Hydrogen Energy | Year: 2015

The implementation and effectiveness of the ability of Nitrogen doped Carbon Nanotube with divacancy (4ND-CNxNT) that is decorated with Sc for Hydrogen adsorption was evaluated with the aide of spin-unrestricted Density Functional Theory formalism. The composite material Sc/4ND-CNxNT has an excellent quality as a media for hydrogen storage characterized by strong binding such that each Sc can hold up to five hydrogen molecules. Detailed structural and electronic properties were reported starting from one up to five hydrogen molecules absorbed. © 2015 Hydrogen Energy Publications, LLC.


Enriquez J.I.G.,De La Salle University - Manila | Villagracia A.R.C.,De La Salle University - Manila | Villagracia A.R.C.,National Research Council of the Philippines
International Journal of Hydrogen Energy | Year: 2016

The effects of different crystallographic defects and substitutional doping of 3d-block transition metals (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn) on the electronic properties and hydrogen molecule (H2) interaction of penta-graphene (PG) were investigated using density functional theory calculations. Electronic properties of PG show strong dependence on PG's structural configuration and the type of metal dopants used. Doping PG with transition metals (TM) may be used to change PG from being a wide band gap semiconductor to a narrow band gap semiconductor or a semimetal. PG have H2 adsorption energies (Eads) that are superior to graphene, with Eads between -0.7 eV and -0.9 eV depending on the adsorption site. Transition metals act as proton rich dopant, and induced positive electrostatic potential in its adjacent regions. Thus, doping improve H-2 adsorption, especially when substituted on sp2 hybridized carbon site. The V-doped and Ti-doped sheets, with Eads of -0.351 eV and -0.319 eV, respectively, show the greatest potential for on-board reversible solid-state hydrogen molecule storage application. © 2016 Hydrogen Energy Publications LLC.


Mananghaya M.,De La Salle University - Manila | Mananghaya M.,National Research Council of the Philippines
Journal of the Korean Chemical Society | Year: 2015

The binding ability and hydrogen storage capacity of nitrogen doped carbon nanotube with divacancy (4ND-CNxNT) that is decorated with transition metals was investigated based on density functional theory calculations. Results indicate that scandium shows an ideal reversible hydrogen binding capability with promising system-weight efficiency compared with other transition metals when functionalized with 4ND-CNxNT. The (Sc/4ND)10-CNxNT can store up to 50H2 molecules, corresponding to a maximum gravimetric density of 5.8 wt%. Detailed structural stability and electronic properties were reported as hydrogen molecules were absorbed. It takes about 0.16 eV/H2 to add one H2 molecule, which assures reversible storage of H2 molecules under ambient conditions.


Mananghaya M.,De La Salle University - Manila | Mananghaya M.,National Research Council of the Philippines
Journal of Molecular Liquids | Year: 2015

The paper discusses the impact of functionalization on understanding the solubility of a single-walled carbon nanotube (SWCNT) to increase its dispersion in water, with the aide of spin-unrestricted density functional theory (DFT). A finite (10, 0) zigzag nanotube model containing 80 C atoms saturated with hydrogen at the ends was investigated with DFT. The (10, 0) SWCNTs were functionalized with: (a) carboxylic acid, (b) aromatic dicarboxylic acid and (c) aminotriethylene glycol, which can be derived from the carboxylic acid. The functionalization is thermodynamically stable and bonding is favorable. The results show an enhancement in the solubility of the nanotubes in water due to increased dipole moment as visualized in the HOMO-LUMO surface plots. Further as the degree of sidewall functionalization increases, the SWCNT sample becomes more soluble as assessed by the calculated Gibbs free energies of solvation. © 2015 Elsevier B.V. All rights reserved.


Torres R.C.,Industrial Technology Development Institute | Torres R.C.,National Research Council of the Philippines | Garbo A.G.,Industrial Technology Development Institute | Walde R.Z.M.L.,National Research Council of the Philippines
Journal of Animal and Plant Sciences | Year: 2015

This study was conducted to investigate the effect of the ethanol and hexane extracts of the fruit wastes of Garcnia mangostana (mangosteen) on the Dengue vector Aedes aegypti.The fruit wastes (pericarp, crown and seeds) were solvent extracted separately. The larvicidal activity of the extracts was tested against the 3rd and 4th instars larvae of the Aedes aegypti following the World Health Organization bioassay method (2005). Characterization of the extracts was conducted by qualitative phytochemical screening. The ethanol pericarp extract of G. mangostana exhibited the highest toxicity among the other parts (crown and seeds) against A. aegypti larvae with an LC50 values of 4.84 mg/L and 6.19 mg/L and LC90 values of 14.55 mg/L and 28.71 mg/L while the hexane extract yielded an LC50 and LC90 of 27.61 mg/L and 67.27 mg/L, respectively. The hexane crown extract also yielded larvicidal activity with an LC50 and LC90 of 25.33 mg/L and 63.73 mg/L, respectively while the ethanol extract gave an LC50 of 63.00 mg/L and LC90 of 169.91 mg/L. Meanwhile, both ethanol and hexane extracts of the seeds did not exhibit any toxic effect up to 500 mg/L and 300 mg/L, respectively. Results suggest the potential of G. mangostana fruit wastes as a key source for the development of environment-friendly plant-based larvicides. © 2015, Pakistan Agricultural Scientists Forum. All Rights Reserved.


PubMed | Industrial Technology Development Institute and National Research Council of the Philippines
Type: | Journal: Asian Pacific journal of tropical medicine | Year: 2014

To evaluate the toxicity of the ethanol and hexane extracts of the different parts of Persea americana Mill. (P. americana) toward third and fourth instars larvae of Aedes aegypti (Ae. aegypti) and to characterize the ethanol extract by qualitative phytochemical analysis.The seeds, peels and pulp of P. americana were processed for crude extraction using 95% ethanol and n-hexane. Crude extracts were bio-assayed for larvicidal activity against Ae. aegypti following the World Health Organization standard bioassay method. The mortality was observed at 24 h and 48 h after treatment and data were subjected to probit analysis to determine lethal concentrations (LC50 and LC90). The ethanol extract was characterized by phytochemical analysis.Both the hexane and ethanol extracts from the different parts of P. americana exhibited evidence of larvicidal toxicity. The hexane extract from the seeds exhibited the highest toxicity with LC50 and LC90 values of 9.82 mg/L and 22.19 mg/L, respectively, while the ethanol seed extract exhibited LC50 of 16.48 mg/L and LC90 45.77 mg/L, respectively. This was closely followed by the ethanol extract of the peels with an LC50 of 10.35 mg/L and LC90 of 26.29 mg/L. The pulp extracted with ethanol also yielded great larvicidal toxicity with LC50 of 21.32 mg/L and LC90 of 59.45 mg/L. Results of the phytochemical analysis of the ethanol seed extract indicated presence of alkaloids, tannins, saponins, unsaturated steroids and triterpenoids, flavonoids (leucoanthocyanins), fats and oils.Both the hexane and ethanol extracts of P. americana showed promising potential as an alternative source of a more sustainable, non-toxic and environmentally friendly solution for the control of dengue vector, Ae. aegypti.

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