Search Results
Abstract
Traditional medicinal seeds prescribed for specific treatment purposes, were purchased from local markets and analyzed by INAA. The samples were irradiated at Es-Salam research reactor, at a power of 5 MW for 6 h. The accuracy of the method was established by analyzing reference materials. Twenty elements were measured, with good accuracy and reproducibility. The concentration of elements determined, was found to vary depending on the seeds. The daily intake of essential and toxic elements was determined, and compared with the recommended values. The probable cumulative intake of toxic elements is well below the tolerance limits.
Abstract
Quantitative data on trace elements in two tobacco leaf (candidate) reference materials OTL-1 and VTL-2 prepared by the Polish Academy of Sciences and the Institute of Nuclear Chemistry and Technology, Warsaw, Poland, are presented and compard to recommended values, where available. By instrumental neutron activation analysis (INAA), as well as by radiochemical technique (RNAA) 30 elements were quantitatively determined and fair agreement was found between the results and recommended values for the first material.
to maintain L. casei viability above the minimum recommended value during storage. The analysis of the viability of probiotic bacteria in the mango nectar samples revealed that the stability of L. casei during storage time was improved by the
Summary
Under an IAEA project for upgrading of reference materials, a new determination of the 129I concentration in the IAEA-375 reference material was performed. A chemical procedure was set up for the preparation of the AgI samples. Measurement of 129I was carried out using the IsoTrace Tandetron AMS facility at University of Toronto. To ensure the accuracy of the calibration, the tuning of the AMS system was iterated using not only the QC (quality control) samples but also all unknown samples. To minimize any possible current-dependent effects between 129I and 127I ions in the injection magnet, low Cs+ sputtering beam intensity (10 μA) was used. The reproducibility in determining the 129I/127I ratio in the IAEA-375 AgI samples was less than 1%. The activity concentration (C A) of 129I in the IAEA-375 reference material was determined to be 1.59±0.08 mBq . kg-1 at 95% confidence level. The present value is about 7% lower than the IAEA recommended value (1.7 mBq . kg-1) listed in 2000 or 20% lower than the recommended value (2 mBq . kg-1) listed in the IAEA AQCS Reference Material Catalogue (2002-2003). Since the IAEA recommended values for IAEA-375 materials was issued about 10 years ago and error range of the recommended values were large, the results we obtained might be useful in upgrading the recommended value.
reduce these health problems ( Swales, 2001 ). According to a study of WHO in 2009, 181 of the 187 countries in the world consume more salt than the recommended value of 5 g per day. Data from 2009 show that salt intake in Hungary was 14.8 g per day for
Abstract
Extensive use of pan, by one-tenth of world"s population, entails the evaluation of trace element contents in its ingredients. Radiochemical neutron activation analysis (RNAA) was developed and successfully employed to determine the concentration of 36 trace elements (essential, toxic and nonessential) in its four basic ingredients, leaf of betel pepper, betel nut, catechu and lime. The radiochemical separation methodology has significantly improved the detection limits of most of these elements due to suppression of Compton background. This study provides the base-line values of certain toxic and essential elements in these ingredients. The daily intake of essential and toxic elements through pan was estimated and compared with the recommended values. The cumulative intake of Mn is four times higher than the recommended value and that of toxic elements is well below the tolerance limits.
Summary
Extensive use of coffee, by one-third of world's population, entails the evaluation of trace element contents in it. Instrumental neutron activation analysis (INAA) was successfully employed to determine the concentration of 20 trace elements (essential, toxic and nonessential) in four samples of coffee beans of various origins and two instant coffee brands most commonly consumed in Pakistan. This study provides the base-line values of certain toxic and essential elements in coffee. The daily intake of essential and toxic elements through coffee was estimated and compared with the recommended values. The cumulative intake of Mn is four times higher than the recommended value and that of toxic elements is well below the tolerance limits.
Some thermodynamic aspects of nitrides in materials science
Fluorine bomb calorimetry study
Abstract
The energies of combustion in fluorine of gallium nitride and indium nitride in wurzite crystalline structure have been measured in a two-compartment calorimetric bomb, and new standard molar enthalpies of formation have been calculated: Δf H m 0(GaN(cr) 298.15 K)= –(163.74.2) kJ mol–1 and Δf H m 0(InN(cr) 298.15 K)= –(146.54.6) kJ mol–1 . Comparison with the recommended values of the Δf H m 0 nitrides from the literature is also presented.
Abstract
In the present work, the concentration of the 14 elements Br, Ca, Cl, Co, Cs, Fe, K, Mn, Na, Rb, Sc Se and Zn have been determined by INAA in diets of four different groups: (a) 19 pre-school children, (b) 18 healthy adults, (c) 23 elderly people living in private institutions and (d) 19 patients with chronic renal failure (CRF). The contents of proteins, lipids and carbohydrates were also analysed in the diets. The daily intakes of the elements analysed were compared to the recommended values set by RDA or WHO.
Abstract
A radiochemical neutron activation analysis (RNAA) combustion method coupled with a neutron exposure normalization technique was used to determine low 
g/kg mercury levels in three National Institute of Standards and Technology (NIST) Standard Reference Materials (SRMs). Two coals (sub-bituminous and bituminous) and a diet material were analyzed. The results obtained provided recommended values of approximately 5 g/kg for SRM 1548a Typical Diet, 24 g/kg for SRM 1635 Trace Elements in Coal (sub-bituminous), and 100 g/kg for SRM 1632b Trace Elements in Coal (bituminous).
