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  • Author or Editor: S. Waheed x
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Abstract  

Instrumental neutron activation analysis (INAA) and atomic absorption spectrophotometry (AAS) were used to verify the protocols for the quantification of zinc and magnesium in human whole blood. A study was conducted on group of volunteers consisting of 131 patients having cardiovascular diseases (CVD) and 23 malignant hypertension (MH) patients along with 432 control subjects with 218 male and 214 females. The elemental data of these elements has been exploited to establish the base line values in control subjects. The possibility of any relationship between blood Mg and Zn levels with CVD and MH has also been investigated. The mean blood Mg and Zn levels were found to be depleted in both CVD and MH patients as compared to normal subjects. In our findings Mg and Zn were found to have an inverse relation with systolic and diastolic pressure. The reliability of the methods was checked by the concurrent analysis of the IAEA reference material (RM) employing the optimized INAA and AAS protocols. The determined values by both techniques were found to be in good agreement with the IAEA reference values. The elemental data in whole blood samples of normal volunteers has also been compared with Mg and Zn contents reported by other countries.

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Abstract  

To understand the role of Cu and Zn in human blood both in controls as well as in cardiovascular (CVD) patients, whole blood samples of 181 CVD and 185 controls between the ages of 20–66 years were investigated. Instrumental neutron activation analysis (INAA) and flame atomic absorption spectrophotometric techniques were successfully employed to quantification Cu and Zn levels. The mean blood-Cu levels (1.50 mg L−1) were found as enhanced whereas Zn levels (5.88 mg L −1) were reduced in cardiovascular patients group as compared to 0.90 and 6.70 mg L−1 for Cu and Zn respectively in controls. Cu/Zn ratios for CVD patients are also higher than in control subjects. Negative correlation exists between Cu and Zn levels in both controls and patient groups. However, when the CVD patients were checked for their systolic and diastolic pressure it was found that copper concentrations in these patients was significantly increased (p < 0.001) with the rise of blood systolic pressure so a positive correlation was observed between copper and systolic pressure. Zn on the other hand has an inverse relation with systolic as well as diastolic pressure (p < 0.001). Total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol, and triglyceride (TG) in blood samples have also been determined and their probable role in the CVD complication has been observed. A positive correlation of blood-Cu with TC, TG, and LDL-C indicates that rise in blood-Cu levels may initiate the development of CVD. An increase in Cu/Zn ratio can instigate the cardiovascular risk factor. The findings from this study can definitely update our knowledge of the role of Cu and Zn in the development of CVD risk in humans.

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Abstract  

The IAEA conducted the IAEA-CU-2006-06 Proficiency Test (PT) on “The determination of major, minor and trace elements in ancient Chinese ceramic” in 2006. The results of this PT showed that of the 21 analytes reported by our laboratory 9 failed the precision criteria. Therefore the results reported by our laboratory along with the results of other laboratories which carried out analysis using neutron activation analysis (NAA) were studied. It was found that the major factor contributing towards data falling in the “Warning” category, failing the precision criteria was the high uncertainties cited in the certificates of the reference materials (RMs) used for quantification of data. In this regard, it is recommended that synthetic standards should be prepared and used on a routine basis especially for the measurement of the elements K, Eu, Lu, Ta, Tb and Yb.

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Abstract  

A radiochemical neutron activation analysis procedure has been applied to investigate 40 major, minor, and trace impurities in nickel-based alloy. The extensive use of these alloys in the electronic industry, telecommunications, manufacturing of aircraft engine turbine blades and chemical equipments desires for their precise characterization. The concentration of nickel in the nickel-based alloy was found to be 56.8%, whereas Fe, Cr, Ca, Mg, Ce, Mn, Na and V were the major components of the alloy, which constituted to more than 26%. The rest of the elements was present in minor or trace levels. Most of the rare earth elements except Ce were also present in trace amounts. Neutron activation analysis technique was preferably used because of its good sensitivity and multielement determination capabilities for the characterization of high purity materials. The comparison of RNAA and INAA indicated improvement in the detection limits utilizing radiochemical separation procedures developed in the present work.

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Abstract  

Instrumental neutron activation analysis has been used to evaluate potentially toxic trace element concentrations in twenty-three individual food items commonly consumed in a high altitude region (Kashmir) as a continuation of our previous study. Elemental intake levels of As, Br, Hg, Sb, and Se per person per day in meat, poultry, food grains, vegetables, fruits and milk have been calculated to assess the safety of dietary intake of these items. The dietary intake values have also been compared to the RDA levels. The data will provide the base-line levels of toxic elements in food items of this region. It will also help the dieticians to formulate safe and adequate diets for the residents of this region.

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Abstract  

Instrumental neutron activation analysis (INAA) have been used to determine As, Br, Hg, Sb and Se in combination with atomic absorption spectrometry (AAS) as a complementary technique for the quantification of Cd and Pb in jaggery, brown sugar, white sugar and molasses. All sugar cane products were collected from the local sugar cane industry of Pakistan. The highest concentration of these potentially toxic elements was quantified in molasses; however, molasses together with jaggery, brown sugar and white sugar contains trace amounts of all of these elements. Due to very low concentration of Cd it could only be detected in molasses. To evaluate the percentage contribution of these elements in the sugar cane products to the weekly recommended values, intakes on weekly consumption of 100 g of each item have also been calculated which follow the pattern Br>Se>Pb>Hg>As>Sb. The elevated Br contents may be attributed to the use of Br-containing chemicals for fumigation; however, these contents are well within the tolerance levels. The estimated weekly intake of all toxic elements is very low indicating that sugar cane products can be safely ingested as part of the diets.

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Abstract  

Five varieties of rice have been analyzed to study the prevailing concentration and distribution of 10 trace elements in rice and rice husk. NAA in combination with AAS has been utilized for the determination of Hg, Pb, Cd, As, Br, Sb, Se, Ni, Al and Cs. The elemental ratios of rice to husk and within rice have been calculated to get information regarding their uptake channels. The daily supply of the elements to the human body has been estimated and from these the safety of the diet has been assessed by comparing with the suggested tolerance levels. A global distribution pattern of some of these elements in rice has also been evaluated.

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Abstract  

An instrumental neutron activation analysis technique has been utilized to study the prevailing levels of certain inorganic trace elements in different varieties of rice produced in Pakistan. The data have been compared with those of other countries. The elemental ratios within rice and rice to husk have been computed to evaluate indirectly the impact of soil and environment on the rice crops. The dietary spectum for the inhabitants of Rawalpindi/Islamabad areas has been evaluated by estimating the daily intake and comparing with allowances suggested in the literature.

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Abstract  

The International Atomic Energy Agency Marine Environmental Laboratory (IAEA-MEL) conducted an intercomparison exercise for the “Trace elements and methyl mercury in fish scallop: IAEA-452” in 2009. The Neutron Activation Analysis (NAA) laboratory at PINSTECH, Pakistan took part in this exercise. Comparison with the IAEA results showed that of the 18 elements reported to the IAEA 7 had unacceptable z-scores while the data for two elements was questionable (2< |z-score| <3). Upon investigation it was discovered that the large number of elements having unacceptable z-scores was due to human error and the greater difficulty in analyzing biological samples which have low amounts of trace elements. Therefore selection of values corresponding to matrix matched reference materials (RMs), such as IAEA-436 and IAEA-407, and to non-interfering peaks the results obtained became comparable to the IAEA results with only the result for As having |z-score|> 3.

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Abstract  

A proficiency test (PT) exercise was offered by the International Atomic Energy Agency (IAEA) for major, minor and trace elements in Chinese ceramic reference material (IAEA-CU-2006-06). Neutron activation analysis (NAA) laboratory at PINSTECH, Pakistan participated in the exercise and submitted the results for 28 elements. The aim of participation was to develop a suitable methodology for accurate measurement of as many elements as possible in ceramic material using a low power reactor (PARR-2) as this would help future investigation in a project on the authenticity of art objects, for provenance, conservation and management of ancient cultural heritage of the country. After receiving the final report of the PT exercise, a critical review of our data and final scoring of each element is made to check the suitability of our methodology and reliability of the acquired data. Most of the reported results passed different statistical evaluation criterion such as relative bias, z-score and u-scores and ratio of our results and IAEA target values. One element (Yb) falls in the unacceptable range of relative bias and z-scores. Hf and Tb showed slightly high z-scores within the questionable range. Ho, Mo and Sn were determined during this study but their results were not submitted to the IAEA. The confidence of accuracy observed for most of the elements in ceramic material has made it mandatory to report their results as information values.

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