Philippine Nuclear Research Institute

Diliman Primero, Philippines

Philippine Nuclear Research Institute

Diliman Primero, Philippines
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Ebajo V.D.,De La Salle University - Manila | Aurigue F.B.,Philippine Nuclear Research Institute | Brkljaca R.,RMIT University | Urban S.,RMIT University | Ragasa C.Y.,De La Salle University - Manila
International Journal of Pharmacognosy and Phytochemical Research | Year: 2015

Chemical investigation of the dichloromethane extracts of Hoya wayetii Kloppenb. afforded β-amyrin cinnamate (1) and taraxerol (2) from the stems; and 2, triglycerides (3), chlorophyll a (4), and a mixture of β-sitosterol (5a) and stigmasterol (5b) from the leaves. The structures of 1 and 2 were elucidated by extensive 1D and 2D NMR spectroscopy, while those of 3-5b were identified by comparison of their NMR data with those reported in the literature. © 2015, International Journal of Pharmacognosy and Phytochemical Research. All rights reserved.

Feliciano C.P.,University of Tsukuba | Feliciano C.P.,Philippine Nuclear Research Institute | Nagasaki Y.,University of Tsukuba
Biomaterials | Year: 2017

The active participation of an anti-inflammatory drug in the biological pathways of inflammation is crucial for the achievement of beneficial and therapeutic effects. This study demonstrated the development of redox nanoparticles that can circulate in the blood at significantly high levels, thus increasing their efficacy as an oral treatment against the deleterious effects of reactive oxygen species (ROS) in an in vivo inflammatory skin model. To confirm the blood bioavailability of the nanoparticles, mice were injected with the nanoparticles solution (RNPN) via oral gavage. Using electron spin resonance and radioactive labeling techniques, the blood circulation of the redox polymer that forms the nanoparticles was confirmed 24 h after oral administration. This contrasted with its low molecular weight counterpart (NH2-TEMPO), which peaked 15 min post injection and was found to be cleared rapidly within minutes after the peak. We then tested its efficacy in the inflammatory skin model. Kud:Hr-hairless mice were irradiated with UVB (302 nm) to induce skin damage and inflammation. Throughout the entire period of UVB irradiation, RNPN was administered to mice by free drinking. NH2-TEMPO was used as the control. The results showed that oral supplementation of RNPN significantly improved the therapeutic effects of the core nitroxide radical compared with its low molecular weight counterpart. Furthermore, RNPN significantly reduced UVB-induced skin aging, epidermal thickening, edema, erythema, skin lesions, and various pathological skin inflammatory disorders in vivo. From the obtained data, we concluded that the use of long-circulating redox nanoparticles (RNPN) provided an effective treatment against the damaging effects of excessive ROS in the body. © 2017 Elsevier Ltd

Asuncion A.J.,Ateneo de Manila University | Asuncion A.J.,Philippine Nuclear Research Institute | Guerrero R.A.,Ateneo de Manila University
Applied Optics | Year: 2017

Quasi-Bessel beams (QBB) with different profiles are generated with an axicon-telescope system. Beam profiles are found to vary with different axicon-telescope distance δ. QBBs are stored as volume holograms in a photorefractive crystal. Reconstructions of the QBBs are focused by the recording axicon to produce superimposed Bessel beams (SBBs) with oscillating cores. SBBs formed through this method have different oscillation periods that range from 4.3 to 6.1 cm. We demonstrate that periodicity is dependent on δ. Our method allows tunability of the SBB period through a simple rearrangement of optical elements. © 2017 Optical Society of America.

Barba B.J.D.,Philippine Nuclear Research Institute | Tranquilan-Aranilla C.,Philippine Nuclear Research Institute | Abad L.V.,Philippine Nuclear Research Institute
Radiation Physics and Chemistry | Year: 2016

Various raw materials and hydrogels prepared from their combination were assessed for hemostatic capability using swine whole blood clotting analysis. Initial screening showed efficient coagulative properties from κ-carrageenan and its carboxymethylated form, and α-chitosan, even compared to commercial products like QuikClot Zeolite Powder. Blending natural and synthetic polymers formed into hydrogels using gamma radiation produced materials with improved properties. KC and CMKC hydrogels were found to have the lowest blood clotting index in granulated form and had the higher capacity for platelet adhesion in foamed form compared to GelFoam. Possible mechanisms involved in the evident thrombogenicity of the materials include adsorption of platelets and related proteins that aid in platelet activation (primary hemostasis), absorption of water to concentrate protein factors that control the coagulation cascade, contact activation by its negatively charged surface and the formation of gel-blood clots. © 2015 Elsevier Ltd.

Abad L.V.,Philippine Nuclear Research Institute | Relleve L.S.,Philippine Nuclear Research Institute | Racadio C.D.T.,Philippine Nuclear Research Institute | Aranilla C.T.,Philippine Nuclear Research Institute | De la Rosa A.M.,Philippine Nuclear Research Institute
Applied Radiation and Isotopes | Year: 2013

The antioxidant capacity of irradiated κ-, ι-, λ-carrageenans were investigated using the hydroxyl radical scavenging assay, reducing power assay and DPPH radical scavenging capacity assay. The degree of oxidative inhibition increased with increasing concentration and dose. The type of carrageenan had also an influence on its antioxidant activity which followed the order of lambda

Feliciano C.P.,Philippine Nuclear Research Institute | De Guzman Z.M.,Philippine Nuclear Research Institute | Tolentino L.M.M.,Philippine Nuclear Research Institute | Cobar M.L.C.,Philippine Nuclear Research Institute | Abrera G.B.,Philippine Nuclear Research Institute
Food Chemistry | Year: 2014

Usually in hospitals low-bacterial diets are served to immuno-compromised patients (ICPs). However, low-bacterial diets still pose a high risk of microbial infections and limit the food selection of the patients. Thus, pathogen-free dishes must be made available. This study presents the development of pathogen-free ready-to-eat (RTE) Filipino ethnic food chicken breast Adobo, sterilized by exposure to high-dose gamma rays (25 kGy) in combination with conventional treatments. Frozen vacuum-packed samples artificially inoculated with Escherichia coli, Listeria monocytogenes, Bacillus cereus, Staphylococcus aureus and Salmonella enterica subsp. enterica serovar Typhimurium, were exposed to 25 kGy gamma radiation for complete sterilization. Microbial quality and sterility of the samples were analysed following 15, 30, and 60 days of storage at -4 °C. The effects of high-dose gamma irradiation on the nutritional quality and sensory characteristics of RTE chicken breast Adobo were also evaluated. © 2014 Elsevier Ltd. All rights reserved.

Obra G.B.,Philippine Nuclear Research Institute | Resilva S.S.,Philippine Nuclear Research Institute
Journal of Applied Entomology | Year: 2013

Enhancement of the sterile male performance in Bactrocera philippinensis through access to protein (yeast hydrolysate) and/or exposure to methyl eugenol (ME) was investigated in this study. The temporal occurrence of sexual maturity of B. philippinensis was determined for both laboratory sterile and wild flies. Laboratory tests were also conducted to determine the peak age of ME feeding in relation to male fly age and sexual maturity and effect of protein on the longevity of sterile males. Field cage mating tests were performed to examine the effect of adult diet (P+ vs. P-) and ME exposure (ME+ vs. ME-) on the mating competitiveness of the sterile male B. philippinensis. P+ME+ sterile male flies achieved significantly more matings with wild females than P+ME- or PE-ME- sterile males. Based on the relative sterile index, P+ sterile male flies were significantly more sexually competitive when competing for wild females than P- flies. The results confirm that the pre-release diet can be significantly improved to increase the effectiveness of the application of the sterile technique against B. philippinensis. © 2011 Blackwell Verlag, GmbH.

Madrid J.F.,Philippine Nuclear Research Institute | Madrid J.F.,University of the Philippines at Diliman | Nuesca G.M.,University of the Philippines at Diliman | Abad L.V.,Philippine Nuclear Research Institute
Radiation Physics and Chemistry | Year: 2013

Water hyacinth fibers (Eichhornia crassipes) were functionalized using radiation-induced graft polymerization of glycidyl methacrylate by γ-rays from 60Co source. The simultaneous grafting technique was employed wherein the water hyacinth fibers were irradiated in nitrogen atmosphere in the presence of glycidyl methacrylate dissolved in water/methanol solvent. The effects of different grafting parameters to the grafting yield were evaluated. The optimal values of solvent, absorbed dose, dose rate, and concentration of monomer were found to be 1:3 (volume/volume) water-methanol solvent, 10kGy, 8kGyh-1 dose rate and 5% volume/volume glycidyl methacrylate, respectively. Using the optimum conditions, degree of grafting of approximately 58% was achieved. The grafted water hyacinth fibers were characterized using Attenuated Total Reflectance-Fourier Transformed Infrared Spectroscopy (ATR-FTIR), Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDX). The results of these tests confirmed the successful grafting of glycidyl methacrylate onto water hyacinth fibers. © 2012 Elsevier Ltd.

Tranquilan-Aranilla C.,Philippine Nuclear Research Institute | Nagasawa N.,Japan Atomic Energy Agency | Bayquen A.,University of the Philippines at Manila | Dela Rosa A.,Philippine Nuclear Research Institute
Carbohydrate Polymers | Year: 2012

Carboxymethyl derivatives of kappa-carrageenan (KC) with varying degrees of substitution were obtained by multi-step carboxymethylation process. The structural and chemical profiles of the derivatives were determined by FT-IR, 13C NMR, gel permeation chromatography (GPC), elemental analysis, potentiometric titration and visual estimation of gelation temperature. The derivatives exhibited high degrees of substitution (DS) and acidity. However, sulfur content, molecular weight (Mw) and gelation temperature were lower compared to the parent KC polymer. FT-IR confirmed the presence of carboxymethyl (CM) groups in the polymer backbone while 13C NMR revealed that functionalization occurred at the three hydroxyl groups in kappa-carrageenan disaccharide unit. © 2011 Elsevier Ltd. All rights reserved.

Madrid J.F.,Philippine Nuclear Research Institute | Abad L.V.,Philippine Nuclear Research Institute
Radiation Physics and Chemistry | Year: 2015

Modified microcrystalline cellulose (MCC) was prepared through gamma radiation-induced graft polymerization of glycidyl methacrylate (GMA). Simultaneous grafting was employed wherein MCC with GMA in methanol was irradiated with gamma radiation in nitrogen atmosphere. The effects of different experimental factors such as monomer concentration, type of solvent and absorbed dose on the degree of grafting, Dg, were studied. The amount of grafted GMA, expressed as Dg, was determined gravimetrically. Information from grafted samples subjected to Fourier transformed infrared spectroscopy (FTIR) in attenuated total reflectance (ATR) mode showed peaks corresponding to GMA which indicates successful grafting. The X-ray diffraction (XRD) analysis revealed that the crystalline region of MCC was not adversely affected after grafting with GMA. The thermogravimetric analysis (TGA) data showed that the decomposition of grafted MCC occurred at higher temperature compared to the base MCC polymer. © 2015 Elsevier Ltd.

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