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101.
Correlation between radionuclides associated with zircon and monazite in beach sand of Rosetta,Egypt
A. Nada T. M. Abd EL-Maksoud H. Abu Zeid I. E. El-Asy S. M. I. Mostafa S. A. Abd El-Azeem 《Journal of Radioanalytical and Nuclear Chemistry》2012,291(3):601-610
The study aims to evaluate the activity concentrations of 238U, 232Th, 40K and 137Cs along Rosetta beach, Egypt. Non-destructive assay techniques were carried out using HP-Ge spectrometer and binocular microscope.
The results of this study serve as a database for radioactivity levels of the mineral sand deposits of Rosetta area. The activity
concentrations of 238U, 232Th and 40K ranged from 5.39 to 134.2, 6.6 to 160.8 and 57.6 to 492 Bqkg−1 respectively. The range of activity concentrations of 137Cs is between 0.05 and 0.91 Bqkg−1. The total gamma absorbed dose rates varied from 11.59 to 160.01 nGyh−1 with a mean value of 50.53 nGyh−1. These values correspond to an annual effective dose equivalent of 0.01–0.2 mSvy−1 with a mean of 0.07 mSvy−1, which is in agreement with the worldwide average. Also, a correlation between the calculated zircon and monazite radioactive
mineral contents with the measured radioactive isotopes was carried out to determine the contribution of each mineral for
radioactivity. These correlations predicted that both zircon and monazite minerals are the main contributors for radioactivity
in the Egyptian beach black sands. Also the present study ensured that area under investigation is to be safe for public. 相似文献
102.
Tatjana Tomić Sandra Babić Nada Uzorinac Nasipak Maja Fabulić Ruszkowski Livijana Škrobonja Marija Kaštelan-Macan 《Journal of chromatography. A》2009,1216(18):3819-3824
Alkene content determinations in fluid catalytic cracking (FCC) liquid products were performed by means of normal-phase high-performance liquid chromatography (NP-HPLC) with diode array detection (UV/DAD). Separation of alkenes from aromatic hydrocarbons was performed on amino-modified silica gel column with n-heptane as mobile phase. The column has a little affinity to alkenes and saturated hydrocarbons and a pronounced affinity to aromatic compounds. The problem of alkenes and saturates co-elution on this column type was overcome with the detection system, UV/DAD, sensitive and selective to alkenes, while saturates are inactive in UV field. Total alkene content was determined as a sum of mono- and dialkene groups quantified by external standard method. Validation and verification of the developed method proved their applicability. The following criteria were used to validate the HPLC–DAD method: selectivity, linearity, precision, limits of detection and quantification. Alkene contents were quantified with the external standard method of wide calibration range, so both low and high alkene contents can be determined by the single calibration. Correlation coefficients were higher than 0.99. Precision was evaluated as repeatability and intermediary precision with relative standard deviations less than 5%. Some structural investigation of alkene groups was performed to confirm the assumption. Proposed method was compared with certified NMR method. Six commercial motor gasoline samples were analyzed by these two methods. Obtained results indicate good agreement between alkene content determined by both methods. The developed method was applied to the determination of alkene content in liquid FCC products in the boiling range from 70 °C to 190 °C. 相似文献
103.
A Nag DS Chung DS Dolzhnikov NM Dimitrijevic S Chattopadhyay T Shibata DV Talapin 《Journal of the American Chemical Society》2012,134(33):13604-13615
Colloidal semiconductor nanocrystals (NCs) provide convenient "building blocks" for solution-processed solar cells, light-emitting devices, photocatalytic systems, etc. The use of inorganic ligands for colloidal NCs dramatically improved inter-NC charge transport, enabling fast progress in NC-based devices. Typical inorganic ligands (e.g., Sn(2)S(6)(4-), S(2-)) are represented by negatively charged ions that bind covalently to electrophilic metal surface sites. The binding of inorganic charged species to the NC surface provides electrostatic stabilization of NC colloids in polar solvents without introducing insulating barriers between NCs. In this work we show that cationic species needed for electrostatic balance of NC surface charges can also be employed for engineering almost every property of all-inorganic NCs and NC solids, including photoluminescence efficiency, electron mobility, doping, magnetic susceptibility, and electrocatalytic performance. We used a suite of experimental techniques to elucidate the impact of various metal ions on the characteristics of all-inorganic NCs and developed strategies for engineering and optimizing NC-based materials. 相似文献
104.
Nada A. Imam N. El Aassy Ibrahim E. Ghanem A. 《Journal of Radioanalytical and Nuclear Chemistry》2019,322(2):347-359
Journal of Radioanalytical and Nuclear Chemistry - This research focused on studying the effect of sulfuric acid concentrations on the leaching of different radionuclides (238U and 235U series) in... 相似文献
105.
Synthesis of the seco-Limonoid BCD Ring System Identifies a Hsp90 Chaperon Machinery (p23) Inhibitor
Dr. David M. Pinkerton Dr. Sharon Chow Nada H. Eisa Kashish Kainth Timothy J. Vanden Berg Dr. Jed M. Burns Assoc. Prof. Luke W. Guddat Dr. G. Paul Savage Prof. Ahmed Chadli Prof. Craig M. Williams 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(6):1451-1455
D-Ring-seco-limonoids (tetranortriterpenoids), such as gedunin and xylogranin B display anti-cancer activity, acting via inhibition of Hsp90 and/or associated chaperon machinery (e.g., p23). Despite this, these natural products have received relatively little attention, both in terms of an enabling synthetic approach (which would allow access to derivatives), and as a consequence their structure–activity relationship (SAR). Disclosed herein is a generally applicable synthetic route to the BCD ring system of the seco-D-ring double bond containing limonoids. Furthermore, cell based assays revealed the first skeletal fragment that exhibited inhibition of the p23 enzyme at a level which was equipotent to that of gedunin, despite being much less structurally complex. 相似文献
106.
Nada Y. Tashkandi Emily E. Cook Jeremy L. Bourque Prof. Kim M. Baines 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(39):14006-14012
The reaction of benzyl isocyanide, tert‐butyl isocyanide, and 2,6‐dimethylphenyl isocyanide with tetramesityldigermene (Mes2Ge=GeMes2) was examined. Whereas the addition of benzyl isocyanide gave the C?NC activation product, Mes2Ge(CH2Ph)Ge(CN)Mes2, tert‐butyl isocyanide, and 2,6‐dimethylphenyl isocyanide did not give stable adducts, rather the rate of conversion of the digermene to the corresponding cyclotrigermane was accelerated. A comparison between the reactivity of the isocyanides with Mes2Ge=GeMes2 and the Ge(100)‐2×1 surface was made and some insights into the surface chemistry are offered. 相似文献
107.
JPC – Journal of Planar Chromatography – Modern TLC - The chromatographic behavior of four groups of s-triazine derivatives (14 compounds) has been studied by TLC on silica gel... 相似文献
108.
A simple, sensitive, and rapid Spectrophotometric method for the trace determination of aniline in aqueous solution is described. The method is based on coupling aniline with diazotizedp-nitroaniline in the presence of ethanol and sodium hydroxide to form an intense red water-soluble azo-dye which shows maximum absorption at 505 nm and greater stability and sensitivity in the presence of cetyltrimethylammonium bromide. Beer's law is obeyed over the aniline concentration range 0.2–2.4g/ml in the solution measured; the molar absorptivity is 3.46×104l· mole–1·cm–1, and the relative standard deviation 1–2%, depending on the aniline concentration. 相似文献
109.
Kundakovic T Fokialakis N Magiatis P Kovacevic N Chinou I 《Chemical & pharmaceutical bulletin》2004,52(12):1462-1465
Investigation of the aerial parts of Achillea alexandri-regis led to the identification of 19 chemical constituents: twelve 3-O-fatty acid esters of triterpene alcohols arnidiol (1-4), maniladiol (5-8) and 16beta-hydroxylupeol (9-12), alpha-amyrin, beta-amyrin, beta-sitosterol, 3,4-O-dicaffeoyl quinic acid, cinnamic acid, pinoresinol-beta-D-glucoside and rutin. Among them, compounds 3, 4, 8, 11 and 12 are new natural products. The structures of all compounds have been elucidated on the basis of their spectral and chemical data. 相似文献
110.
Moreau L Camplo M Wathier M Taib N Laguerre M Bestel I Grinstaff MW Barthélémy P 《Journal of the American Chemical Society》2008,130(44):14454-14455
Supramolecular assembly formation resulting from molecular recognition between complementary nucleolipids has been visualized in real time at the micrometer scale. 相似文献