Search Results
Abstract
There has been a significant research effort on the development of an oil industry based on Australian oil shales. However, to date the research has been based mainly on the processing aspects of oil shale. The thermal analyses of oil shales, while having been the subject of many studies, have been limited to some extent by instrumentation and analytical techniques. This paper reports on thermal analysis studies utilising traditional thermogravimetry/differential thermal analysis (TG/DTA) and differential scanning calorimetry (DSC). The application of modern thermal analysis techniques such as high resolution TG (HRTG) and modulated differential scanning calorimetry (MDSC) is also examined and compared to the traditional methods.
Summary
Sandia National Laboratories collects bioassay samples to monitor individuals for possible exposure to uranium and thorium as part of ongoing medical surveillance of employees. The current analytical methods involve separation chemistry and alpha-spectrometry for isotopic measurements or kinetic phosphorescence analysis for total uranium. There are several areas where this monitoring can be improved (e.g., analysis times and accurate isotopic ratio measurements). In addition, in case of accidents or exposure to people who are not routinely monitored, the optimum window for collecting bioassay samples may be missed. An example of this scenario is the recent concern over the exposure of civilians to depleted uranium from military ammunition in Kosovo and Kuwait. For these cases, hair may be an alternative bioassay. Analytical procedures utilizing an inductively coupled plasma mass spectrometer (ICP-MS) have been developed that have simplified sample processing and improved the isotopic ratio measurements. The focus of this study is to survey the background levels for 235U, 236U, 238U, and 232 Th isotopes in hair, urine, and drinking water which could be used to determine action levels for follow-up monitoring. In addition, variations of 238U to 235U mass ratio for the background samples are measured. The analytical procedures, achieved detection limits, observed background distributions, and the results of uranium isotope ratio tests are presented.
Abstract
Nuclear medicine and radiotherapy make a vital contribution to the diagnosis and treatment of major disease. This role is likely to expand with new developments including availability of new medical isotopes. A European network (EMIR) was initiated in 2001 by the Joint Research Centre (JRC) of the European Commission, to identify and solve difficulties that constrain nuclear medicine and radiotherapy development in Europe and facilitate closer interdisciplinary collaboration. Participating organisations include the main European associations of medical radiation specialists, radiopharmaceutical/radioisotope producers, nuclear research reactor institutions, research organizations and the JRC. The steering committee established task groups focusing on eight key areas for development. Liaison with non-European organizations will be encouraged.
Summary
Copper-61 produced via the natZn(p,x)61Cu nuclear reaction was used for the preparation of [61Cu]diacetyl-bis(N4-methylthiosemicarbazone) ([61Cu]ATSM) (4) using a house-made ATSM ligand. After a proton irradiation of an electroplated zinc layer by 22 MeV protons at 180 mA for 3.2 hours, 61Cu was recovered by two-step chromatography using a cation and an anion exchange column. About 222 GBq (6.00 Ci) of 61Cu2+ was obtained with a radiochemical separation yield of more than 95% and a radionuclidic purity of better than 99%. Colorimetric methods showed that traces of chemical impurities in the product were below the accepted limits. The [61Cu]ATSM production was optimized for reaction conditions (buffer concentration and temperature) with a radiochemical yield of higher than 80%, radiochemical purity of better than 98% and a specific activity of about 246 Ci/mmol. The produced [61Cu]ATSM is a PET radiotracer for hypoxia imaging with an intermediate half life and a satisfactory quality, suitable for future PET studies.
Summary
One of the high-level natural radiation areas (HLNRAs) in Iran is located in the south of Iran in the Hormozgan province. Uranium and its daughters, such as radium and thorium cause areas of elevated natural radiation. An unknown hypothermal mineral and radioactive spring was discovered containing high-level radiation, 42 mSv . y-1 maximum effective dose around spring was measured. 40K, 226Ra and 232Th radionuclides were detected with the maximum activity of 11.80 Bq . l-1, 3.48 Bq . l-1 and 2.52 Bq . l-1, respectively. These activities are the second highest in comparison to those in the Ramsar radioactive springs, especially Ab-e-siah spring, which contains 146.5 Bq . l-1 activity. Ocillatoria spp., Lyngbya spp. and a kind of ciliatawere observed in this spring. The results showed that the radioactive spring falls into the sodium chloride category.
Carbon dioxide chemistry is an area of continuing growth in recent times, due to socioeconomic and environmental reasons. Several methods have now been reported for obtaining N-methylation on primary and secondary amines directly from CO2. We have translated in two microfluidic setups (Slug Flow [SF] and Tube-in-Tube [TiT]) a ruthenium (Ru)-catalyzed process previously reported using a pressure vessel. Here, we demonstrate how the SF approach is more efficient but requires more input to reach a steady state, while the TiT system is less efficient but more tuneable.We have tested these processes on three model amines and two radiopharmaceutical precursors that are routinely used in 11C chemistry. The microfluidic processes tested are also potentially more efficient than the pressure vessel counterpart, in terms of amount of Ru catalyst needed (1% vs. 10%) and projected reaction completion time.
Abstract
Two natural zeolites from Iranian deposits (clinoptilolite and natrolite) were characterized and their ability for adsorption of iodide from nuclear wastewaters was evaluated. The adsorption behavior was studied on natural and modified zeolites by g-spectrometry using 131I as radiotracer. Adsorption isotherms and distribution coefficient (Kd) were measured. The results showed that clinoptilolite is a more promising zeolite for removal of iodide compared to natrolite. Furthermore, the adsorption was higher in silver, lead and thallium forms, whereas the lowest desorption was observed in lead modified zeolite.
Abstract
Radiotracer method was developed for measuring14CO2 content in cement-wood mixtures. The carbon dioxide used for the treatment was labeled with14C, a 
-emitting radioisotope, and samples were measured by -scintillation and liquid scintillation techniques. Test samples were prepared in the laboratory with various compositions and treated with labeled14CO2. The tracer was released from Ba14CO3 by lactic acid with total activity of 37 MBq. Selectivity of the technique allows to distinguish the carbon dioxide bound during the treatment and bound previously from the mbient air. Sensitivity of the method is higher than that of traditional methods and allowed determination of CO2 content in each component of the mixture. It is 63 ng. if measured by -scintillation detector and 1.6 ng, if measured by liquid scintillation. Accuracy of the method is 0.3%.
Abstract
New165Dy and166Ho macroaggregates(165Dy-MA,166Ho-MA) were prepared by reacting the aqueous solution of165Dy(NO3)3 and166Ho(NO3)3, respectively, with sodium borohydride solution in 0.2N NaOH.165Dy-MA and166Ho-MA are sterile suspension of macroaggregates consisted of Dy/Ho (50–56 wt.%) and boron (5–7%) in saline with mean particle size of 2.6 
m (1–8 m range). Both MA could be prepared from the pre-made164Dy-MA and165Ho-MA followed by neutron irradiation. Even though the165Dy-MA and166Ho-MA suspension in saline were stored at 37°C for 24 hrs (Dy-MA), 10 days (Ho-MA) or autoclaved at 121°C for 30 minutes, there was no significant change in particle size and no leakage problem indicating the prepared165Dy-MA and166Ho-MA are sufficiently stable. The results of in-vivo retention studies using rabbits showed high retention (>99.5%) in knee joint even at 24 hrs (165Dy-MA) or at 10 days (166Ho-MA) after administration. Rabbits treated with intra-articular injections of164Dy-MA or165Ho-MA equivalent to 20–30 times the typical clinical dose showed no signs of any toxic effects at 1 month after administration. The ease with which the165Dy-MA and166Ho-MA can be made in the narrow size range and their high in-vitro and in-vivo stability make them attractive agents for radiation synovectomy.
Two selective and reproducible methods have been established for simultaneous analysis of ambroxol hydrochloride (Amb) and doxycycline hyclate (Dox). The first method is densitometric TLC on silica gel with ethyl acetate-ethanol-glacial acetic acid-water 9:4:0.5:1 ( v/v ) as mobile phase. The linear range was 1–10 μg per zone (equivalent to 100–1000 μg mL −1 ) for both drugs. The second method is high-pressure liquid chromatography (HPLC) on a C 18 column with methanol-0.5 m phosphate buffer, pH 6.5 60:40 ( v/v ) as mobile phase and ultraviolet detection at 254 and 270 nm for Amb and Dox, respectively. This method was linear over the concentration ranges 37.5–750 and 50–750 μg mL −1 for Amb and Dox, respectively. The methods enabled specific and accurate analysis of these drugs in laboratory-prepared mixtures and in Ambrodoxy capsules. The results obtained agreed statistically with those obtained by use of the official B.P. methods.
