scholarly journals Determination of Plutonium Activity Concentrations and 240Pu/239Pu Atom Ratios in Brown Algae (Fucus distichus) Collected from Amchitka Island, Alaska.

2005 ◽  
Author(s):  
T Hamilton ◽  
T Brown ◽  
A Marchetti ◽  
R Martinelli ◽  
S Kehl
2009 ◽  
Vol 282 (2) ◽  
pp. 477-482 ◽  
Author(s):  
Terry Hamilton ◽  
Doug Dasher ◽  
Tom Brown ◽  
Roger Martinelli ◽  
Alfredo Marchetti ◽  
...  

Author(s):  
N N Jibiri ◽  
S O Egwu ◽  
N E Adesiji

Abstract The natural radionuclides content and radiological assessment of sediments of the Ogunpa waste-water channel were evaluated to ascertain the radiological safety of the sediments as a building material. The mean activity concentrations of 40K, 226Ra and 232Th in Bq kg−1 were found to be 171 ± 69, 11 ± 5 and 10 ± 4, respectively. The overall mean radium equivalent 29 ± 13 Bq kg−1 was <370 Bq kg−1 that can give the maximum recommended dose of 1 mSv to the general public. The activity concentrations of the radionuclides were all less than world average for soils and sediments. Thus, the use of the sediments from the Ogunpa water channel as building material is safe and would not pose any significant radiological health hazards.


Author(s):  
Samran Samran ◽  
Dalimunthe Dalimunthe ◽  
Dalimunthe Dalimunthe ◽  
Dalimunthe Dalimunthe

 Objective: Curcuma xanthorrhiza Roxb. was used as hereditary medicinal plant for prevention of liver dysfunction, gastrointestinal disease, fever, and hemorrhoid. Curcuma extract was easy to damage because the light exposure, change of pH, weather and a long period of storage time. The problem can be solved by coating the extract with spray wet microencapsulation (SWM) technique. SWM technique is a method of preparing microcapsules in which a solution, suspension, or emulsion with a charged matrix is sprayed into opposing solution. The aim of this research was to formulate the dry Curcuma extract with SWM technique using sodium alginate as matrix.Methods: Brown algae (Sargassum ilicifolium) was a main resource of alginate acid. It was isolated using HCl 5% to make alginate acid and sodium alginate that was obtained by adding Na2CO3 5% to alginate acid solution. The microencapsulation process of Curcuma extract was done by SWM technique. The formula of Curcuma extract microencapsulation was design into three formulas: F1, F2, and F3. Microcapsules of Curcuma extract were being characterized for color intensity, analysis of scanning electron microscope (SEM), compressibility index, flowing time, and determination of angle repose.Results: The results showed that the higher concentration of sodium alginate used, the dry Curcuma extract microcapsules produced better. Particle size of extract microcapsules of Curcuma extract microcapsules SEM from F1, F2, F3 was 20 μm whereas dry weight of extracted microcapsule of Curcuma grows with increasing concentration of sodium alginate: F1 (0.2%) 19.86±0.11 g, F2 (0.4%) 20.66±0.73, F3 (0.6%) 21.29±0.64. The flowing time of F1, F2, and F3 was 6.92±0.56, 7.42±0.50, and 8.05±0.54 s consecutively.Conclusions: Based on the analysis of the study result, it can be concluded that the raw materials of Curcuma extract can be made by SWM technique using sodium alginate isolated from brown algae, and the characterization of dry Curcuma extract microcapsule of the three formulas met the requirements of the pre-formulation tests for capsule dosage form.


2016 ◽  
Vol 44 ◽  
pp. 1660237
Author(s):  
Huda Al-Sulaiti ◽  
Tabassum Nasir ◽  
K. S. Al Mugren ◽  
N. Alkhomashi ◽  
N. Al-Dahan ◽  
...  

The goal of this study was to establish the first baseline measurements for radioactivity concentration of the artificial radionuclide [Formula: see text]Cs in soil samples collected from the Qatarian peninsula. The work focused on the determination of the activity concentrations levels of man-made radiation in 129 soil samples collected across the landscape of the State of Qatar. All the samples were collected before the most recent accident in Japan, “the 2011 Fukushima Dai-ichi nuclear power plant accident”. The activity concentrations have been measured via high-resolution gamma-ray spectrometry using a hyper-pure germanium detector situated in a low-background environment with a copper inner-plated passive lead shield. A radiological map showing the activity concentrations of [Formula: see text]Cs is presented in this work. The concentration was[Formula: see text]found to range from 0.21 to 15.41 Bq/kg. The highest activity concentration of [Formula: see text]Cs was observed in sample no. 26 in North of Qatar. The mean value was found to be around 2.15 ± 0.27 Bq/kg. These values lie within the expected range relative to the countries in the region. It is expected that this contamination is mainly due to the Chernobyl accident on 26 April 1986, but this conclusion cannot be confirmed because of the lack of data before this accident.


2011 ◽  
Vol 40 (3) ◽  
pp. 1-8 ◽  
Author(s):  
Tamara Zalewska ◽  
Michał Saniewski

Abstract137Cs activity concentrations were determined in macrophytes and macrozoobenthic organisms from the southern Baltic Sea. Cesium isotope content was analysed in macroalgae species (green, red and brown algae representatives) and in some species of vascular plants. The analyzed macroinvertebrate organisms included bivalves and a crustacean.Concentration factors (CF) were calculated using the determined 137Cs concentration in the flora and fauna organisms against that in seawater, and the bioaccumulative properties were compared. The study pointed out that the most important factors in the cesium bioaccumulation process occurring in plants are related to morphology. The highest CF values were obtained in algae Polysiphonia fucoides, Ectocarpus siliculosus and Cladophora glomerata. Decidedly lower CF values were observed in the vascular plants and macrozoobenthos representatives.


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