Dalat Nuclear Research Institute

Da Lat, Vietnam

Dalat Nuclear Research Institute

Da Lat, Vietnam
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Tran T.H.,Kyushu University | Tran T.H.,Dalat Nuclear Research Institute | Okabe H.,Kyushu University | Hidaka Y.,Kyushu University | Hara K.,Kyushu University
Carbohydrate Polymers | Year: 2017

Sodium Carboxymethyl Cellulose (CMC[sbnd]Na)/Sodium Styrene Sulfonate (SSS) hydrogels with grafted and crosslinked polymeric networks were prepared by γ-radiation at atmosphere condition. The obtained hydrogels were characterized by gel fraction, swelling ratio, TGA and FTIR spectroscopy. The results showed the ratio of CMC and SSS 1:0 gave the highest gel fraction, compared with other ratios. The swelling capacity increased by increasing SSS content due to the presence of [sbnd]SO3Na, [sbnd]OH groups in gel structure. The FTIR spectrum of CMC/SSS gel showed the new absorption peaks at 1034 and 1012 cm−1 corresponds to [sbnd]SO3Na group. The metal ion adsorption capacity of CMC/SSS gel was investigated. The grafted gel effectively removed metal ions, especially Cr and Pb. The effects of hydrogel composition, contact time, and initial concentration on the adsorption capacity of the grafted hydrogels were studied. The adsorption kinetics and equilibrium isotherms were investigated using pseudo-second-order model and Langmuir model. © 2016

Hoi T.X.,Ho Chi Minh City University of Natural Sciences | Phuong H.T.,University of Science | Van Hung N.,Dalat Nuclear Research Institute
Applied Radiation and Isotopes | Year: 2016

During the production of iodine-131 from neutron irradiated tellurium dioxide by the dry distillation, a considerable amount of 131I vapor is dispersed to the indoor air. People who routinely work at the production area may result in a significant risk of exposure to chronic intake by inhaled 131I. This study aims to estimate the inhalation dose for individuals manipulating the 131I at a radioisotope production. By using an application installed on smartphones, we collected the time-microenvironment data spent by a radiation group during work days in 2015. Simultaneously, we used a portable air sampler combined with radioiodine cartridges for grabbing the indoor air samples and then the daily averaged 131I concentration was calculated. Finally, the time-microenvironment data jointed with the concentration to estimate the inhalation dose for the workers. The result showed that most of the workers had the annual internal dose in 1÷6 mSv. We concluded that using smartphone as a motion detector is a possible and reliable way instead of the questionnaires, diary or GPS-based method. It is, however, only suitable for monitoring on fixed indoor environments and limited the targeted people. © 2016 Elsevier Ltd

Hoi T.X.,Phu Yen University | Phuong H.T.,University of Science | Van Hung N.,Dalat Nuclear Research Institute
Radiation Protection Dosimetry | Year: 2017

Besides the most common methods of internal dose assessment from inhaled 131I, that are thyroid monitoring and urine ana lysis, air sampling is a possible way but rarely used for dose estimate. This study aimed to focus on the utilisation of portable air sampler to estimate the internal dose for workers working at 131I production facility. In addition, internal dose estimated from urine analysis at the same time was carried out for comparison. Based on this research, it was found that air monitoring can be done efficiently as urine monitoring if the following conditions are met: (1) the indoor areas are not large, (2) sampling sites need to be placed as near breathing zone as possible and (3) the time-micro-environment patterns of monitored workers are collected carefully.

Long N.Q.,Institute of Nuclear Science and Technology | Truong Y.,Dalat Nuclear Research Institute | Hien P.D.,Vietnam Atomic Energy Agency | Binh N.T.,Dalat Nuclear Research Institute | And 3 more authors.
Journal of Environmental Radioactivity | Year: 2012

Radionuclides from the reactor accident at the Fukushima Dai-ichi Nuclear Power Plant were observed in the surface air at stations in Hanoi, Dalat, and Ho Chi Minh City (HCMC) in Vietnam, about 4500 km southwest of Japan, during the period from March 27 to April 22, 2011. The maximum activity concentrations in the air measured at those three sites were 193, 33, and 37 μBq m -3 for 131I, 134Cs, and 137Cs, respectively. Peaks of radionuclide concentrations in the air corresponded to arrival of the air mass from Fukushima to Vietnam after traveling for 8 d over the Pacific Ocean. Cesium-134 was detected with the 134Cs/ 137Cs activity ratio of about 0.85 in line with observations made elsewhere. The 131I/ 137Cs activity ratio was observed to decrease exponentially with time as expected from radioactive decay. The ratio at Dalat, where is 1500 m high, was higher than those at Hanoi and HCMC in low lands, indicating the relative enrichment of the iodine in comparison to cesium at high altitudes. The time-integrated surface air concentrations of the Fukushima-derived radionuclides in the Southeast Asia showed exponential decrease with distance from Fukushima. © 2011 Elsevier Ltd.

PubMed | i Army Medical and Veterinary Research Center, ag Institute Chemii i Techniki Jadrowej, d NRF iThemba LABS, z Institute Investigaciones Biologicas Clements Estable and 34 more.
Type: Journal Article | Journal: International journal of radiation biology | Year: 2016

Two quality controlled inter-laboratory exercises were organized within the EU project Realizing the European Network of Biodosimetry (RENEB) to further optimize the dicentric chromosome assay (DCA) and to identify needs for training and harmonization activities within the RENEB network.The general study design included blood shipment, sample processing, analysis of chromosome aberrations and radiation dose assessment. After manual scoring of dicentric chromosomes in different cell numbers dose estimations and corresponding 95% confidence intervals were submitted by the participants.The shipment of blood samples to the partners in the European Community (EU) were performed successfully. Outside the EU unacceptable delays occurred. The results of the dose estimation demonstrate a very successful classification of the blood samples in medically relevant groups. In comparison to the 1st exercise the 2nd intercomparison showed an improvement in the accuracy of dose estimations especially for the high dose point.In case of a large-scale radiological incident, the pooling of ressources by networks can enhance the rapid classification of individuals in medically relevant treatment groups based on the DCA. The performance of the RENEB network as a whole has clearly benefited from harmonization processes and specific training activities for the network partners.

PubMed | Dalat Nuclear Research Institute, Nanyang Technological University and National University of Singapore
Type: | Journal: European journal of pharmaceutics and biopharmaceutics : official journal of Arbeitsgemeinschaft fur Pharmazeutische Verfahrenstechnik e.V | Year: 2016

The conventional bulk mixing method to prepare amorphous drug-polysaccharide nanoparticle complex (or drug nanoplex in short) has a major drawback in the lack of size control for the nanoplex produced, hence limiting its potential applications as a supersaturating drug delivery system for bioavailability enhancement of poorly soluble drugs. For this reason, we developed a continuous millifluidic synthesis platform of the drug nanoplex exhibiting high size tunability using curcumin (CUR) and chitosan (CHI) as the models for drug and polysaccharides, respectively. The nanoplex size tunability was achieved by controlling the residence time of the CUR and CHI solutions in the millifluidic reactor, where their slow diffusive mixing at the liquid-liquid interface resulted in a well-regulated nanoplex growth as a function of the residence time. The effects of the preparation pH, molecular weight of CHI, millifluidic tube diameter, and flowrate on the nanoplex size tunability were investigated from which the optimal preparation condition was determined. At the optimal condition, the CUR nanoplex was roughly 115nm in size with zeta potential of 15mV and 72% (w/w) CUR payload. The millifluidic synthesis also maintained the high CUR utilization rate (80%) exhibited by the bulk mixing method. Most importantly, the ability to produce significantly smaller nanoplex (sixfold smaller) via millifluidics led to the generation of higher (8.5 of CUR saturation solubility) and prolonged (8h) supersaturation level. These results bode well for the bioavailability enhancement potential of the drug nanoplex.

Sang N.D.,Can Tho University | Van Hung N.,Dalat Nuclear Research Institute | Van Hung T.,Research and Development Center for Radiation Technology | Hien N.Q.,Research and Development Center for Radiation Technology
Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms | Year: 2017

The kinetic parameters of thermoluminescence (TL) glow peaks of chilli powder irradiated by gamma rays with the different doses of 0, 4 and 8 kGy have been calculated and estimate by computerized glow curve deconvolution (CGCD) method and the R package tgcd by using the TL glow curve data. The kinetic parameters of TL glow peaks (i.e. activation energies (E), order of kinetics (b), trapping and recombination probability coefficients (R) and frequency factors (s)) are fitted by modeled general-orders of kinetics (GOK) and one trap-one recombination (OTOR). The kinetic parameters of the chilli powder are different toward the difference of the sample time-storage, radiation doses, GOK model and OTOR one. The samples spending the shorter period of storage time have the smaller the kinetic parameters values than the samples spending the longer period of storage. The results obtained as comparing the kinetic parameters values of the three samples show that the value of non-irradiated samples are lowest whereas the 4 kGy irradiated-samples’ value are greater than the 8 kGy irradiated-samples’ one time. © 2017 Elsevier B.V.

Tan V.H.,Agency for Radiation and Nuclear Safety | Son P.N.,Dalat Nuclear Research Institute
Journal of Physics: Conference Series | Year: 2016

The thermal neutron radiative capture cross section for186W(n, γ)187W reaction was measured by the activation method using the filtered neutron beam at the Dalat research reactor. An optimal composition of Si and Bi, in single crystal form, has been used as neutron filters to create the high-purity filtered neutron beam with Cadmium ratio of Rcd = 420 and peak energy En = 0.025 eV. The induced activities in the irradiated samples were measured by a high resolution HPGe digital gamma-ray spectrometer. The present result of cross section has been determined relatively to the reference value of the standard reaction197Au(n, γ)198Au. The necessary correction factors for gamma-ray true coincidence summing, and thermal neutron self-shielding effects were taken into account in this experiment by Monte Carlo simulations. © Published under licence by IOP Publishing Ltd.

Son P.N.,Dalat Nuclear Research Institute | Hai N.X.,Dalat Nuclear Research Institute
Journal of Physics: Conference Series | Year: 2016

Precise information on the decay heat from fission products following times after a fission reaction is necessary for safety designs and operations of nuclear-power reactors, fuel storage, transport flasks, and for spent fuel management and processing. In this study, the timing distributions of fission products' concentrations and their integrated decay heat as function of time following a fast neutron fission reaction of232Th were exactly calculated by the numerical method with using the DHP code. © Published under licence by IOP Publishing Ltd.

PubMed | University of Science, Dalat Nuclear Research Institute and Ho Chi Minh City University of Natural Sciences
Type: | Journal: Radiation protection dosimetry | Year: 2016

Besides the most common methods of internal dose assessment from inhaled

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