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Terrestrial Gamma Radiation in Phuket Island, Thailand  [cached]
Supitcha Chanyotha,Chutima Kranrod,Shinji Tokonami,Napakan Suwankot
Engineering Journal , 2011, DOI: 10.4186/ej.2011.15.4.65
Abstract: The aim of this study was to evaluate the level of terrestrial radioactivity on Phuket Island, which used to be the richest tin province in Thailand. We measured 124 survey points of terrestrial gamma dose rate at one meter above the surface of local soil along roads in the environs of Phuket Island. Another 31 survey points were examined inside an old ore-dressing plant. The terrestrial gamma dose rate of the Island (excluding the abandoned area of the old dressing plant) ranges from 20 to 900 nGy h-1, while the geometric mean Island value was 190 nGy h-1. Soil samples were also collected from selected areas having high gamma dose rates to analyze for activity concentrations of 226Ra, 232Th and 40K. Based on these soil activities, the calculated terrestrial gamma dose rate found to range between 25 and 520 nGy h-1. The corresponding annual effective doses varied between 0.03 and 0.6 mSv y-1. The results of the terrestrial gamma dose rate obtained from direct measurement in the old tin dressing plant ranged from 110-17,170 nGy h-1 with a mean value of 1410 nGy h-1. The terrestrial gamma dose rate calculated from soil samples in the dressing plant ranged from 590 to 206,080 nGy h-1 which corresponding to annual effective dose of 0.7-250 mSv y-1. Thus, the dose rates on much of Phuket Island are within typical background values while the dose rates within the old tin dressing plant are elevated by as much as 16 times background.
Gamma radiation exposure of MCT diode arrays  [PDF]
F. F. Sizov,I. O. Lysiuk,J. V. Gumenjuk-Sichevska,S. G. Bunchuk,V. V. Zabudsky
Physics , 2006, DOI: 10.1088/0268-1242/21/3/026
Abstract: Investigations of electrical properties of long-wavelength infrared (LWIR) mercury cadmium telluride (MCT) arrays exposed to gamma-radiation have been performed. Resistance-area product characteristics of LWIR n{+}-p photodiodes have been investigated using microprobe technique at T=78 K before and after an exposure to various doses of gamma-radiation. The current transport mechanisms for those structures are described within the framework of the balance equation model taking into account the occupation of the trap states in the band gap.
The observation of Gamma Ray Bursts and Terrestrial Gamma-ray Flashes with AGILE  [PDF]
E. Del Monte,G. Barbiellini,F. Fuschino,A. Giuliani,F. Longo,M. Marisaldi,S. Mereghetti,E. Moretti,M. Trifoglio,G. Vianello,E. Costa,I. Donnarumma,Y. Evangelista,M. Feroci,M. Galli,I. Lapshov,F. Lazzarotto,P. Lipari,L. Pacciani,M. Rapisarda,P. Soffitta,M. Tavani,S. Vercellone,S. Cutini,F. Boffelli,A. Bulgarelli,P. Caraveo,P. W. Cattaneo,A. Chen,G. Di Cocco,F. Gianotti,C. Labanti,A. Morselli,A. Pellizzoni,F. Perotti,G. Piano,P. Picozza,M. Pilia,M. Prest,G. Pucella,A. Rappoldi,S. Sabatini,E. Striani,A. Trois,E. Vallazza,V. Vittorini,L. A. Antonelli,C. Pittori,B. Preger,P. Santolamazza,F. Verrecchia,P. Giommi,L. Salotti
Physics , 2011, DOI: 10.1016/j.nima.2010.06.050
Abstract: Since its early phases of operation, the AGILE mission is successfully observing Gamma Ray Bursts (GRBs) in the hard X-ray band with the SuperAGILE imager and in the MeV range with the Mini-Calorimeter. Up to now, three firm GRB detections were obtained above 25 MeV and some bursts were detected with lower statistical confidence in the same energy band. When a GRB is localized, either by SuperAGILE or Swift/BAT or INTEGRAL/IBIS or Fermi/GBM or IPN, inside the field of view of the Gamma Ray Imager of AGILE, a detection is searched for in the gamma ray band or an upper limit is provided. A promising result of AGILE is the detection of very short gamma ray transients, a few ms in duration and possibly identified with Terrestrial Gamma-ray Flashes. In this paper we show the current status of the observation of Gamma Ray Bursts and Terrestrial Gamma-ray Flashes with AGILE.
Antibacterial, antifungal and cytotoxic activity of terrestrial cyanobacterial strains from Serbia
Zorica Svircev,Dragana Cetojevic-Simin,Jelica Simeunovic,Maja Karaman,Dejan Stojanovic
Science China Life Sciences , 2008, DOI: 10.1007/s11427-008-0115-8
Abstract: Cyanobacteria are known to be a rich source of biologically active compounds some of which can have pharmaceutical importance. In this work we present the screening results of cyanobacterial strains for their antibacterial, antifungal, and cytotoxic activity. Cyanobacterial strains were isolated from various soil types in province of Vojvodina and Central Serbia, Republic of Serbia. The screening included 9 strains of Anabaena and 9 strains of Nostoc. Both, extracellular products (from the culture liquid) and cellular crude lipophilic extracts were tested against 13 bacterial strains and 8 fungal strains. Cytotoxic activity was tested against three human cell lines. Methanol extracts were prepared according to stensvik. Antibacterial and antifungal activities were determined measuring inhibition zone, 48 h after inoculation. The cytotoxic activity was determined by sulforhodamine B (SRB) colorimetric assay. Of all cyanobacterial strains tested, 52% showed some antifungal and 41% antibacterial activity. Two out of six tested strains possessed cytotoxic activity. The cytotoxic activity of Anabaena strain S12 was found both in culture liquid and crude cell extract. It occurred specifically between the 21st and 42nd day of cultivation against HeLa and MCF7 cells, but had no activity against cell line derived from a healthy tissue. A high percentage of the active strains among the tested strains justify the effort of screening cyanobacteria that are isolated from terrestrial environments. The most promising strains for the further study are Anabaena strain S12 which showed strong cytotoxic and antibacterial activity and Anabaena strain S20 which produces a potent antifungal compound. The future work, besides further screening and chemical identification of the active compounds, should also include the development of culture techniques that would lead to more efficient production of biologically active compounds.
Antibacterial, antifungal and cytotoxic activity of terrestrial cyanobacterial strains from Serbia

Zorica Svircev,Dragana Cetojevic-Simin,Jelica Simeunovic,Maja Karaman,Dejan Stojanovic,

中国科学C辑(英文版) , 2008,
Abstract: Cyanobacteria are known to be a rich source of biologically active compounds some of which can have pharmaceutical importance. In this work we present the screening results of cyanobacterial strains for their antibacterial, antifungal, and cytotoxic activity. Cyanobacterial strains were isolated from various soil types in province of Vojvodina and Central Serbia, Republic of Serbia. The screening included 9 strains of Anabaena and 9 strains of Nostoc. Both, extracellular products (from the culture liquid) and cellular crude lipophilic extracts were tested against 13 bacterial strains and 8 fungal strains. Cytotoxic activity was tested against three human cell lines. Methanol extracts were prepared according to stensvik. Antibacterial and antifungal activities were determined measuring inhibition zone, 48 h after inoculation. The cytotoxic activity was determined by sulforhodamine B (SRB) colorimetric assay. Of all cyanobacterial strains tested, 52% showed some antifungal and 41% antibacterial activity. Two out of six tested strains possessed cytotoxic activity. The cytotoxic activity of Anabaena strain S12 was found both in culture liquid and crude cell extract. It occurred specifically between the 21st and 42nd day of cultivation against HeLa and MCF7 cells, but had no activity against cell line derived from a healthy tissue. A high percentage of the active strains among the tested strains justify the effort of screening cyanobacteria that are isolated from terrestrial environments. The most promising strains for the further study are Anabaena strain S12 which showed strong cytotoxic and antibacterial activity and Anabaena strain S20 which produces a potent antifungal compound. The future work, besides further screening and chemical identification of the active compounds, should also include the development of culture techniques that would lead to more efficient production of biologically active compounds.
Gamma-Ray Localization of Terrestrial Gamma-Ray Flashes  [PDF]
M. Marisaldi,A. Argan,A. Trois,A. Giuliani,M. Tavani,C. Labanti,F. Fuschino,A. Bulgarelli,F. Longo,G. Barbiellini,E. Del Monte,E. Moretti,M. Trifoglio,E. Costa,P. Caraveo,P. W. Cattaneo,A. Chen,F. D'Ammando,G. De Paris,G. Di Cocco,G. Di Persio,I. Donnarumma,Y. Evangelista,M. Feroci,A. Ferrari,M. Fiorini,T. Froysland,M. Galli,F. Gianotti,I. Lapshov,F. Lazzarotto,P. Lipari,S. Mereghetti,A. Morselli,L. Pacciani,A. Pellizzoni,F. Perotti,P. Picozza,G. Piano,M. Pilia,M. Prest,G. Pucella,M. Rapisarda,A. Rappoldi,A. Rubini,S. Sabatini,P. Soffitta,E. Striani,E. Vallazza,S. Vercellone,V. Vittorini,A. Zambra,D. Zanello,L. A. Antonelli,S. Colafrancesco,S. Cutini,P. Giommi,F. Lucarelli,C. Pittori,P. Santolamazza,F. Verrecchia,L. Salotti
Physics , 2010, DOI: 10.1103/PhysRevLett.105.128501
Abstract: Terrestrial Gamma-Ray Flashes (TGFs) are very short bursts of high energy photons and electrons originating in Earth's atmosphere. We present here a localization study of TGFs carried out at gamma-ray energies above 20 MeV based on an innovative event selection method. We use the AGILE satellite Silicon Tracker data that for the first time have been correlated with TGFs detected by the AGILE Mini-Calorimeter. We detect 8 TGFs with gamma-ray photons of energies above 20 MeV localized by the AGILE gamma-ray imager with an accuracy of 5-10 degrees at 50 MeV. Remarkably, all TGF-associated gamma rays are compatible with a terrestrial production site closer to the sub-satellite point than 400 km. Considering that our gamma rays reach the AGILE satellite at 540 km altitude with limited scattering or attenuation, our measurements provide the first precise direct localization of TGFs from space.
AGILE Observations of Terrestrial Gamma-Ray Flashes  [PDF]
M. Marisaldi,F. Fuschino,C. Labanti,A. Bulgarelli,F. Gianotti,M. Trifoglio,M. Tavani,A. Argan,E. Del Monte,F. Longo,G. Barbiellini,A. Giuliani,A. Trois,for the AGILE collaboration
Physics , 2011,
Abstract: The AGILE satellite, operating since mid 2007 and primarily devoted to high-energy astrophysics, is one of the only three currently operating space instruments capable of detecting Terrestrial Gamma-Ray Flashes (TGFs), together with RHESSI and $Fermi$-GBM. Thanks to the AGILE Mini-Calorimeter instrument energy range extended up to 100MeV and its flexible trigger logic on sub-millisecond time scales, AGILE is detecting more than 10 TGFs/month, adding a wealth of observations which pose severe constrains on production models. The main AGILE discoveries in TGF science during two and a half years of observations are the following: 1) the TGF spectrum extends well above 40 MeV, 2) the high energy tail of the TGF spectrum is harder than expected and cannot be easily explained by previous theoretical models, 3) TGFs can be localized from space using high-energy photons detected by the AGILE gamma-ray imaging detector. In this presentation we will describe the characteristics of the 2.5-years AGILE TGF sample, focusing on the recent results concerning the TGF high-energy spectral characteristics.
Gamma Emitting Radionuclides in Soils from Selected Areas in Douala-Bassa Zone, Littoral Region of Cameroon  [PDF]
Maurice Moyo Ndontchueng,Eric Jilbert Mekongtso Nguelem,Augustin Simo,Raymond Limen Njinga,Gembou Shouop Cébastien Jo?l
ISRN Spectroscopy , 2014, DOI: 10.1155/2014/245125
Abstract: A study of natural radioactivity levels in some composites of eighteen soil samples selected within Douala-Bassa zone of Littoral Region has been evaluated. The samples were analysed using gamma spectrometry based broad energy germanium detector (BEGe 6350). The activity profile of radionuclide shows low activity across the studied areas. The obtained mean values of 226Ra, 232Th, and 40K in the two campuses were 25.48?Bq/kg, 65.96?Bq/kg, and 39.14?Bq/kg for Campus 1 and 24.50?Bq/kg, 66.71?Bq/kg, and 28.19?Bq/kg for Campus 2, respectively. In terms of health analysis, some radiation health hazard parameters were calculated within the two campuses. The mean values of radium equivalent activity were 122.81?Bq/kg and 122.08?Bq/kg, absorbed dose rate in air was 99.13?nGy/h and 98.18?nGy/y, annual outdoor effective dose was 0.12?mSv/y and 0.12?mSv/y, and external health hazard index was 0.34 and 0.33 in Campus 1 and Campus 2, respectively. These health hazard parameters were seen to be below the safe limit of UNSCEAR 2000 except the absorbed dose rate in air and the annual outdoor effective doses which are relatively high compared to the values of 60?nGy/h and 0.07?mSv/y. These results reveal no significant radiological health hazards for inhabitance within the study areas. 1. Introduction Gamma radiation emitted from naturally occurring radioisotopes, also called terrestrial background radiation, represents the main source of radiation of the human body. Natural environmental radioactivity and the associated external exposure due to gamma radiation depend primarily on the geological and geographical conditions and appear at different levels in the soils of each region in the world [1, 2]. Only radionuclides with half-lives comparable with the age of the earth or their corresponding decay products existing in terrestrial materials such as 232Th, 238U, and 40K are of great interest. Abnormal occurrences of uranium and its decay products in rocks and soils and thorium in monazite sands are the main sources of high natural background areas that have been identified in several areas of the world [3]. Outdoors exposure to this radiation originates predominantly from the upper 30?cm of the soil [1]. According to the literature of natural radioactivity in soil, there is lack of information on natural radioactivity levels in soils from various living sites in Cameroon. Radionuclides in soil generate a significant component of the background radiation exposure to the population [3]. The knowledge of specific activities or concentrations and distributions of the
Risk analysis and exposure assessment of Ochratoxin A in Serbia  [cached]
Dragan R. Milicevic,Srdan Stefanovic,Sasa Jankovic,Tatjana Radicevic
Veterinary World , 2012,
Abstract: Aim: The aim of this study was to check the current status of OTA contamination of the Serbian pork and chicken meat in naturally exposed animals which are part of chain production. The knowledge of these factors, their importance and significance, can be used as a tool from the food safety point of view to predict if OTA content in pork and chicken tissues poses a risk to human health and deleterious effects on animals' health and wellbeing. Materials and Methods: A total of 540 samples of pigs blood, kidney, liver and chicken gizzard were randomly selected from slaughtered pigs (n=90) and chicken (n=90) and analyzed for the presence of ochratoxin A (OTA) by High-performance liquid chromatography (HPLC-FL). Results: In porcine tissue samples, of the 90 liver samples, 26.6% contained OTA in the range of 0.22-14.5 ng/g. The incidence of OTA in serum and kidneys were very similar (31% and 33.3%, respectively), with a maximum concentration of 220.8 ng/mL, and 52.5 ng/g, respectively. Majority of chickens' tissues samples, were not found to contain measurable amounts of OTA. Moreover, the OTA levels found in analysed tissues were low in general. Conclusion: The results of this preliminary research indicate that the content of OTA in the examined tissues are far below the values that represent hazard to the health of consumers. However, the results of this study show that in Serbia, consumers are nevertheless frequently exposed to ochratoxins. [Vet. World 2012; 5(7.000): 412-416]
Protective role of Peanut oil in rats exposed to two different doses of gamma radiation that produced oxidative stress and bone injury
Tamer M. M. Saad and Amal A. A. Ammar
Egyptian Journal of Hospital Medicine , 2011,
Abstract: Introduction: Exposure to ionizing radiation represents a genuine, increasing threat to mankind and our environment. The steadily increasing applications of radiation in clinical practice, industrial and agricultural activities, on top of residual radioactivity resulting from nuclear test explosions, have a measurable impact contributing to possible radiation hazards in humans. Control of radiation hazards is considered as one of the most important challenges in order to protect our lives from radiation damages. The trans-3,4,5-trihydroxystibeneis a phyto-chemical present in peanuts and grapes with beneficial effects such as protection against cardiovascular disease and cancer prevention. Purpose: The present study aims to clarify the role of peanut oil as a radioprotector in male albino rats against oxidative stress and bone injury induced by two different doses of gamma irradiation. Material and Methods: Rats were subjected to a dose of 5 Gy (group 3) or 10 Gy ( group 4 ) ( single dose/ whole body ) in comparison with control group ( group 1 ). Prior to the two doses of gamma radiation, rats received peanut oil subcutaneously, ( 0.75 ml/kg ) over one month period, on three days/week ( group 5 and 6 ). Group 2, rats received peanut oil subcutaneously, ( 0.75 ml/kg ) as group 5, but without exposure to radiation. Results: The results showed that whole body gamma irradiation revealed significant acceleration in the level of lipid peroxide (MDA), with significant depletion in glutathione content (GSH), superoxide dismutase (SOD) and catalase (CAT) activities. Meanwhile. Also, the study showed significant increase in serum calcium with concomitant decrease in the bone calcium and significant increase in serum inorganic phosphorous concomitant with a decrease in bone phosphorous after radiation exposure. Administration of peanut oil pre-irradiation has significantly ameliorated the radiation induced disturbance in all the investigated parameters. Conclusion: Metabolism can be controlled to some extent by peanut oil administrated prior to irradiation.
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