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21.
Jabbar A Tufail M Arshed W Bhatti AS Ahmad SS Akhter P Dilband M 《Isotopes in environmental and health studies》2010,46(4):495-505
In Rechna Doab, samples of the most common vegetation, perennial grass Desmostachya bipinnata (dab), were collected along with soil samples from 29 sites. Natural radioactivity of 22?Ra, 232Th/22?Ac and ??K was measured by using high purity germanium-based gamma ray spectrometer. Activity concentration levels of 22?Ra, 232Th/22?Ac and ??K in soil were found to be 46.8 ± 6.2 (36.0-57.6), 61.4 ± 5.9 (48.2-73.2) and 644.8 ± 73.9 (537.7-868.4) Bq kg?1 (dry mass), respectively, and those in vegetation were 2.74 ± 1.70 (1.00-6.39), 2.24 ± 0.59 (1.56-2.61) and 172.72±113.37 (53.14-469.24) Bq kg?1 (dry mass), respectively. The measured values of the activity concentration in vegetation are comparable with some other international data. Calculated soil to vegetation transfer factors of 22?Ra, 22?Ac and ??K were 0.06 ± 0.03 (0.02-0.14), 0.04 ± 0.01 (0.03-0.04) and 0.26 ± 0.16 (0.09-0.69). The mean outdoor absorbed dose rate in air for the area under study was determined as 8.22 nGy h?1 and the mean indoor absorbed dose rate in air was 11.52 nGy h?1. The total annual effective dose to the general public from the vegetation was found to be (0.02-0.16) mSv, which is below the recommended limit value of 1 mSv y?1 for the general public. The dab vegetation under study was found to be radiologically safe for the population and environment. 相似文献
22.
Abdul Jabbar Muhammad Tufail Waheed Arshed Arshed Salem Bhatti Syed Salman Ahmad Perveen Akhter 《Isotopes in environmental and health studies》2013,49(4):495-505
In Rechna Doab, samples of the most common vegetation, perennial grass Desmostachya bipinnata (dab), were collected along with soil samples from 29 sites. Natural radioactivity of 226Ra, 232Th/228Ac and 40K was measured by using high purity germanium-based gamma ray spectrometer. Activity concentration levels of 226Ra, 232Th/228Ac and 40K in soil were found to be 46.8±6.2 (36.0–57.6), 61.4±5.9 (48.2–73.2) and 644.8±73.9 (537.7–868.4) Bq kg?1 (dry mass), respectively, and those in vegetation were 2.74±1.70 (1.00–6.39), 2.24±0.59 (1.56–2.61) and 172.72±113.37 (53.14–469.24) Bq kg?1 (dry mass), respectively. The measured values of the activity concentration in vegetation are comparable with some other international data. Calculated soil to vegetation transfer factors of 226Ra, 228Ac and 40K were 0.06±0.03 (0.02–0.14), 0.04±0.01 (0.03–0.04) and 0.26±0.16 (0.09–0.69). The mean outdoor absorbed dose rate in air for the area under study was determined as 8.22 nGy h?1 and the mean indoor absorbed dose rate in air was 11.52 nGy h?1. The total annual effective dose to the general public from the vegetation was found to be (0.02–0.16) mSv, which is below the recommended limit value of 1 mSv y?1 for the general public. The dab vegetation under study was found to be radiologically safe for the population and environment. 相似文献
23.
Mukhtar Amir Nasir Habib Rashid Badar Waheed Hizba 《Journal of Thermal Analysis and Calorimetry》2019,138(6):3939-3947
Journal of Thermal Analysis and Calorimetry - For effective and reliable ignition of ammonium perchlorate and hydroxyl-terminated polybutadiene (AP/HTPB) solid composite propellant base bleed (BB)... 相似文献
24.
Shobhit S. Chaturvedi Rajeev Ramanan Sodiq O. Waheed Jon Ainsley Martin Evison Jennifer M. Ames Christopher J. Schofield Tatyana G. Karabencheva-Christova Christo Z. Christov 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(21):5422-5426
The human KDM7 subfamily histone H3 Nϵ-methyl lysine demethylases PHF8 (KDM7B) and KIAA1718 (KDM7A) have different substrate selectivities and are linked to genetic diseases and cancer. We describe experimentally based computational studies revealing that flexibility of the region linking the PHD finger and JmjC domains in PHF8 and KIAA1718 regulates interdomain interactions, the nature of correlated motions, and ultimately H3 binding and demethylation site selectivity. F279S an X-linked mental retardation mutation in PHF8 is involved in correlated motions with the iron ligands and second sphere residues. The calculations reveal key roles of a flexible protein environment in productive formation of enzyme-substrate complexes and suggest targeting the flexible KDM7 linker region is of interest from a medicinal chemistry perspective. 相似文献
25.
Ayub Khurram Shahzad Zaman Waqas Qamar Miran Waheed Ali Meesam Abbas Zain Mushtaq Umair Shahzad Asif Yang Ji 《Research on Chemical Intermediates》2022,48(10):4227-4248
Research on Chemical Intermediates - Volatile organic compounds (VOCs) represent a very important class of pollutants that causes serious health effects. There is an urgent requirement to establish... 相似文献
26.
Lilu?Zhang Abdul?Waheed Richard?A.?JonesEmail author Vincent?M.?Lynch 《Journal of chemical crystallography》2005,35(9):673-677
The crystal structure of the bis-amido complex of Ti(IV) (η5-C5H5)2Ti(NH(2,4-(C
CSiMe3)2C6H3))2 is reported. This complex was prepared in 52% yield from the reaction of (η5-C5H5)2TiCl2 with two equivalents of LiNH(2,4-(C
CSiMe3)2C6H3) (prepared in situ in THF at −78∘C). The substituted aniline H2N(2,4-(C
CSiMe3)2C6H3) was prepared in 70% yield from the reaction of 2,4-dibromoaniline with Me3SiC
CH using conventional Pd/Cu coupling methodology. The molecular structure of (η5-C5H5)2Ti(NH(2,4-(C
CSiMe3)2C6H3))2 (monoclinic, space group C2/c, Z = 4, a = 29.7523(5) Å, b = 9.5339(2) Å, c = 15.8864(3) Å, β = 93.022(1)∘ features a titanium (IV) center with a distorted tetrahedral geometry which lies on a crystallographic twofold axis. The amido units are arranged so that steric interactions are minimized. The Ti– N distance is 2.016(2) Å. 相似文献
27.
J. H. Zaidi S. Waheed S. Ahmed 《Journal of Radioanalytical and Nuclear Chemistry》1999,242(2):259-263
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. 相似文献
28.
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. 相似文献
29.
The effect of melting heat transfer on the two dimensional boundary layer flow of a micropolar fluid near a stagnation point embedded in a porous medium in the presence of internal heat generation/absorption is investigated. The governing non-linear partial differential equations describing the problem are reduced to a system of non-linear ordinary differential equations using similarity transformations solved numerically using the Chebyshev spectral method. Numerical results for velocity, angular velocity and temperature profiles are shown graphically and discussed for different values of the inverse Darcy number, the heat generation/absorption parameter, and the melting parameter. The effects of the pertinent parameters on the local skin-friction coefficient, the wall couple stress, and the local Nusselt number are tabulated and discussed. The results show that the inverse Darcy number has the effect of enhancing both velocity and temperature and suppressing angular velocity. It is also found that the local skin-friction coefficient decreases, while the local Nusselt number increases as the melting parameter increases. 相似文献
30.
We study the accelerated expansion of the universe by exploring the Brans-Dicke parameter in different eras. For this, we take the FRW universe model with a viscous fluid (without potential) and the Bianchi type-I universe model with a barotropic fluid (with and without a potential). We evaluate the deceleration parameter and the Brans-Dicke parameter to explore cosmic acceleration. It is concluded that accelerated expansion of the universe can also be achieved for higher values of the Brans-Dicke parameter in some cases. 相似文献