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Summary A comprehensive scheme for the semiquantitative determination of 30 metal ions (Ag+, Pb2+, W6+, Tl+, Fe3+, Au3+, Mo6+, Ga3+, Sb5+, Ge4+, Te4+, Pt4+, Pd2+, Ru3+, Rh3+, Cu2+, Co2+, Ni2+, Zn2+, Cd2+, Cr6+, Mn2+, U6+, V5+, Sn4+, Bi3+, Hg2+, Ti4+, Se4+ and As3+) is described. It is based on circular thin-layer chromatographic technique. The error is ± 5% and 16 other metal ions, not included in the analysis scheme because of the non-availability of spray reagents, do not interfere. The determination of each cation has been made with different spray reagents separately and the mean error has been calculated. The analysis of the same cation with different spray reagents provides a useful check on the results. The method holds an excellent promise for the study of airborne particulates and for the determination of trace elements from blood, tissue and bone.
Zusammenfassung Ein umfassender Analysengang für die halb quantitative Bestimmung von 30 Metallionen wurde beschrieben. Die Ringchromatographie auf Dünnschichten wurde hierzu verwendet. Der Fehler beträgt ±5%. 16 weitere Metallionen, die in Ermangelung geeigneter Sprühreagenzien in den Analysengang nicht aufgenommen wurden, stören nicht. Die Bestimmung jedes einzelnen Kations wurde mit verschiedenen Sprühmitteln vorgenommen; der mittlere Fehler wurde dann berechnet. So ist eine gute Überprüfung der Ergebnisse möglich. Das Verfahren dürfte sich für die Untersuchung der Luftverschmutzung sowie für die Bestimmung von Spurenelementen in Blut, Gewebe und Knochen eignen.相似文献
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Characterization of ion irradiated silicon surfaces ablated by laser-induced breakdown spectroscopy
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Low energy metallic ions,generated by a Q-switched Nd:YAG laser(1064-nm wavelength,10-mJ energy,9-nm~12-ns-pulse width,10~(11)W/cm~2intensity)irradiated on a silicon substrate to modify various properties,such as electrical,morphological,and structural modifications.Thomson parabola technique is used to calculate the energy of these metallic ions whereas the electrical conductivity is calculated with the help of Four-point probe.Interestingly circular tracks forming chain like damage trails are produced via these energetic ions which are carefully examined by optical microscopy.It is observed that excitation,ionization,and cascade collisions are responsible for surface modifications of irradiated samples.Four-point probe analysis revealed that the electrical conductivity of substrate has reduced with increasing trend of atomic number of irradiated metallic ions(Al,Ti,Cu,and Au).The x-ray diffraction analysis elucidated the crystallographic changes leading to reduction of grain size of N-type silicon substrate,which is also associated with the metallic ions used.The decreasing trend of conductivity and grain size is due to thermal stresses,scattering effect,structural imperfections,and non-uniform conduction of energy absorbed by substrate atoms after the ion irradiation. 相似文献
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Asma Hayat Shazia Bashir Muahmamd Shahid Rafique Mahreen Akram Khaliq Mahmood Saman Iqbal Asadullah Dawood Arooj 《Optics and Spectroscopy》2016,120(1):1-8
The optical characteristics of biological tissues sampled from the anterior abdominal wall of laboratory rats are for the first time experimentally studied in a wide wavelength range (350-2500 nm). The experiments have been performed in vitro using a LAMBDA 950 (PerkinElmer, United States) spectrophotometer. Inverse Monte Carlo simulation is used to restore the spectral dependences for scattering and absorption coefficients, as well as the scattering anisotropy factor for biological tissue based on the recorded spectra of diffuse reflection and total and collimated transmissions. 相似文献
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An analysis is performed for the unsteady mixed convection flow of an incompressible viscous fluid about a stagnation point on a stretching sheet in the presence of a variable free stream. The equations of motion and energy are transformed into the ordinary differential equations by using similarity transformations. Homotopy analysis method is used for the solution of the governing problem. The results have been discussed by plots. The present values of the function are shown very close to the previous limiting solutions. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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M. N. Arshad O. Şahin M. Zia-ur-Rehman I. U. Khan A. M. Asiri H. M. Rafique 《Journal of Structural Chemistry》2013,54(2):437-442
The title compound, 4-hydroxy-2H-1,2-benzothiazine-3-carbohydrazide 1,1-dioxide-oxalohydrazide (1:1), is determined using X-ray diffraction techniques and the molecular structure is also optimized at the B3LYP/6-31G(d,p) level using density functional theory (DFT). The asymmetric unit consists of four independent molecules. The oxalohydrazide molecules have the centre of symmetry at the mid-point of the central C-C bond. Each thiazine ring adopts a half-chair conformation. Intermolecular C-H...O, N-H...O and N-H...N hydrogen bonds produce R 2 2 (10), R 2 2 (13), R 3 3 (12) and R 3 3 (15) rings, which lead to one-dimensional polymeric chains. An extensive three-dimensional supramolecular network of N-H...N, N-H...O, C-H...O and O-H...O hydrogen bonds is responsible for crystal structure stabilization. 相似文献
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Yasir Nazir Hummera Rafique Naghmana Kausar Qamar Abbas Zaman Ashraf Pornchai Rachtanapun Kittisak Jantanasakulwong Warintorn Ruksiriwanich 《Molecules (Basel, Switzerland)》2021,26(9)
Targeting tyrosinase for melanogenesis disorders is an established strategy. Hydroxyl-substituted benzoic and cinnamic acid scaffolds were incorporated into new chemotypes that displayed in vitro inhibitory effects against mushroom and human tyrosinase for the purpose of identifying anti-melanogenic ingredients. The most active compound 2-((4-methoxyphenethyl)amino)-2-oxoethyl (E)-3-(2,4-dihydroxyphenyl) acrylate (Ph9), inhibited mushroom tyrosinase with an IC50 of 0.059 nM, while 2-((4-methoxyphenethyl)amino)-2-oxoethyl cinnamate (Ph6) had an IC50 of 2.1 nM compared to the positive control, kojic acid IC50 16700 nM. Results of human tyrosinase inhibitory activity in A375 human melanoma cells showed that compound (Ph9) and Ph6 exhibited 94.6% and 92.2% inhibitory activity respectively while the positive control kojic acid showed 72.9% inhibition. Enzyme kinetics reflected a mixed type of inhibition for inhibitor Ph9 (Ki 0.093 nM) and non-competitive inhibition for Ph6 (Ki 2.3 nM) revealed from Lineweaver–Burk plots. In silico docking studies with mushroom tyrosinase (PDB ID:2Y9X) predicted possible binding modes in the catalytic site for these active compounds. Ph9 displayed no PAINS (pan-assay interference compounds) alerts. Our results showed that compound Ph9 is a potential candidate for further development of tyrosinase inhibitors. 相似文献
8.
Rabail Ujan Pervaiz Ali Channar Aamer Saeed Qamar Abbas Hummera Rafique Saba Ashraf Mahboob Ali Rind Abbas Hassan Anwar Ul-Hamid Mubashar Hassan Hussain Raza Sung-Yum Seo 《Journal of heterocyclic chemistry》2021,58(10):1929-1935
The porcine pancreatic elastase inhibition and free-radical scavenging play a crucial role in age progression. All the series of 10 newly synthesized benzimidazole thioureas ( 4a-j ) were assessed for elastase inhibition and radical scavenging activity to identify the suitable anti-aging ingredient for cosmetics products. The compounds 4e , 4f , 4g , and 4h showed inhibition better than the standard, while compound 4f showed the most significant elastase inhibition with the IC50 value of 1.318 ± 0.025 μM compared with oleanic acid IC50 13.451 ± 0.014 used ±1.989 and 41.563 ± 0.824, respectively, as standard. Molecular docking studies were performed and the compound 4f showed binding energy of 7.2 kcal/mol. Kinetics studies revealed inhibition of the pancreatic elastase in a competitive manner. The relative binding energy and structure activity relationship (SAR) identified compound 4f as an effective inhibitor of porcine pancreatic elastase. Compounds 4e and 4i showed remarkable free-radical scavenging activity with SC50 values of 26.421. 相似文献
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Luana Bettanin Sumbal Saba Fábio Z. Galetto Gustavo A. Mike Jamal Rafique Antonio L. Braga 《Tetrahedron letters》2017,58(50):4713-4716
We describe herein a simple, fast and inexpensive protocol for the oxidative coupling of thiols employing a stoichiometric amount of DMSO and iodine as the catalyst. Various aromatic disulfides were obtained in good to excellent yields in short reaction times at room temperature, while aliphatic disulfides were achieved in good yields when the reactions were conducted under microwave irradiation. 相似文献