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排序方式: 共有215条查询结果,搜索用时 15 毫秒
1.
Selective and Simultaneous Determination of Dihydroxybenzene Isomers Based on Green Synthesized Gold Nanoparticles Decorated Reduced Graphene Oxide 下载免费PDF全文
Selvakumar Palanisamy Chelladurai Karuppiah Shen‐Ming Chen K. Muthupandi R. Emmanuel P. Prakash Mohamed S. Elshikh M. Ajmal Ali Fahad M. A. Al‐Hemaid 《Electroanalysis》2015,27(5):1144-1151
In the present study, we report the simultaneous electrochemical determination of hydroquinone (HQ), catechol (CC) and resorcinol (RC) at gold nanoparticles (Au‐NPs) decorated reduced graphene oxide (RGO) modified electrode. An enhanced and well defined peak current response with a better peak separation of HQ, CC and RC is observed at RGO/Au‐NPs composite than that of RGO and Au‐NPs modified electrodes. The fabricated modified electrode shows a wide linear response in the concentration range of 3–90 µM, 3–300 µM and 15–150 µM for HQ, CC and RC, respectively. The detection limit of HQ, CC and RC is found as 0.15 µM, 0.12 µM and 0.78 µM, respectively. 相似文献
2.
π‐Expanded α,β‐Unsaturated Ketones: Synthesis,Optical Properties,and Two‐Photon‐Induced Polymerization 下载免费PDF全文
Rashid Nazir Dr. Florent Bourquard Evaldas Balčiūnas Dr. Sabina Smoleń Dr. David Gray Prof. Dr. Nikolai V. Tkachenko Dr. Maria Farsari Prof. Dr. Daniel T. Gryko 《Chemphyschem》2015,16(3):682-690
A library of π‐expanded α,β‐unsaturated ketones was designed and synthesized. They were prepared by a combination of Wittig reaction, Sonogashira reaction, and aldol condensation. It was further demonstrated that the double aldol condensation can be performed effectively for highly polarized styrene‐ and diphenylacetylene‐derived aldehydes. The strategic placement of two dialkylamino groups at the periphery of D ‐π‐A‐π‐D molecules resulted in dyes with excellent solubility. These ketones absorb light in the region 400–550 nm. Many of them display strong solvatochromism so that the emission ranges from 530–580 nm in toluene to the near‐IR region in benzonitrile. Ketones based on cyclobutanone as central moieties display very high fluorescence quantum yields in nonpolar solvents, which decrease drastically in polar media. Photophysical studies of these new functional dyes revealed that they possess an enhanced two‐photon absorption cross section when compared with simpler ketone derivatives. Due to strong polarization of the resulting dyes, values of two‐photon absorption cross sections on the level of 200–300 GM at 800 nm were achieved, and thanks to that as well as the presence of the keto group, these new two‐photon initiators display excellent performance so that the operating region is 5–75 mW in some cases. 相似文献
3.
Crocetti Letizia Floresta Giuseppe Nazir Shabnam Vergelli Claudia Bhogal Amrit Biancalani Claudio Cesari Nicoletta Giovannoni Maria Paola Cilibrizzi Agostino 《Structural chemistry》2022,33(3):769-793
Structural Chemistry - We report here synthetic approaches to access new classes of small molecules based on three heterocyclic scaffolds, i.e. 3,7-dihydropyrimido[4,5-d]pyridazine-4,8-dione,... 相似文献
4.
Mahrous Awad M. A. El-Desoky A. Ghallab Jan Kubes S. E. Abdel-Mawly Subhan Danish Disna Ratnasekera Mohammad Sohidul Islam Milan Skalicky Marian Brestic Alaa Baazeem Saqer S. Alotaibi Talha Javed Rubab Shabbir Shah Fahad Muhammad Habib ur Rahman Ayman EL Sabagh 《Molecules (Basel, Switzerland)》2021,26(11)
Accumulation of heavy metals (HMs) by ornamental plants (OPs) from contaminated agriculture soils is a unique technique that can efficiently reduce the metal load in the food chain. Amaranthus tricolor L. has attractive characteristics acquiring a higher growth rate and large biomass when grown at heavy metal contaminated soils. Site-specific detailed information is not available on the use of A. tricolor plant in metal phytoremediation from the polluted sites. The study aimed to enhance the uptake of HMs (Pb, Zn, and Cu) via amending poultry litter extract (PLE), vinasse sugarcane (VSC), and humic acid (HA) as natural mobilized organic materials compared to ethylene diamine tetraacetic acid (EDTA), as a common mobilized chemical agent by A. tricolor plant. The studied soils collected from Helwan, El-Gabal El-Asfar (Cairo Governorate), Arab El-Madabeg (Assiut Governorate), Egypt, and study have been conducted under pot condition. Our results revealed all organic materials in all studied soils, except EDTA in EL-Gabal El-Asfar soil, significantly increased the dry weight of the A. tricolor plant compared to the control treatment. The uptake of Pb and Zn significantly (p > 0.05) increased due to applying all organic materials to the studied soils. HA application caused the highest uptake as shown in Pb concentration by more than 5 times in Helwan soil and EDTA by 65% in El-Gabal El-Asfar soil while VSC increased it by 110% in El-Madabeg soil. Also, an increase in Zn concentration due to EDTA application was 58, 42, and 56% for Helwan, El-Gabal El-Asfar, and El-Madabeg soil, respectively. In all studied soils, the application of organic materials increased the remediation factor (RF) than the control. El-Madabeg soil treated with vinasse sugarcane gave the highest RF values; 6.40, 3.26, and 4.02% for Pb, Zn, and Cu, respectively, than the control. Thus, we identified A. tricolor as a successful ornamental candidate that, along with organic mobilization amendments, most efficiently develop soil health, reduce metal toxicity, and recommend remediation of heavy metal-contaminated soils. Additionally, long-term application of organic mobilization amendments and continued growth of A. tricolor under field conditions could be recommended for future directions to confirm the results. 相似文献
5.
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
6.
Considering the significance of non-Newtonian fluid usage in manufacturing such as molten plastics, polymeric materials, pulps, and so on, significant efforts have been made to investigate the phenomenon of non-Newtonian fluids. In this article the influences of heat and mass transfer on non-Newtonian Walter's B fluid flow over uppermost catalytic surface of a paraboloid is encountered. An elasticity of the fluid layer is considered in the freestream together with heat source/sink and has the tendency to cause heat flow in the fluid saturated domain. The flow problem of two-dimensional Walter's B fluid is represented using Law of conservation of mass, momentum, heat, and concentration along with thermal and solutal chemical reactive boundary conditions. The governing equations are non-linear partial differential equation and are non-dimensionalized by employing stream function and similarity transformation. The final dimensionless equations yielded are coupled non-linear ordinary differential equations. Furthermore, shooting technique along with RK-4th order method is used to get the numerical results. Graphs and tables are modeled by using MATLAB software to check the effects of Walter's B parameter, Chemical reaction parameter and Thickness parameter on temperature, velocity, and concentration profiles. Tabular analysis shows the results of some physical parameters like skin friction coefficient, Nusselt number and Sherwood number due to the variation of Walter's B parameter, thickness parameter and chemical reactive parameter. 相似文献
7.
Arif Rafiq Nazir Ahmad Mir Farooq Ahmad 《应用数学和力学(英文版)》2007,28(7):901-906
In account of the famous Cebysev inequality, a rich theory has appeared in the literature. We establish some new weighted Cebysev type integral inequalities. Our proofs are of independent interest and provide new estimates on these types of inequalities. 相似文献
8.
Nazir Muhammad Shahzad Ghasemi Ali Dezfulizadeh Amin Abdalla Ahmad N. 《Journal of Thermal Analysis and Calorimetry》2021,144(6):2653-2664
Journal of Thermal Analysis and Calorimetry - The aim of this work is the energy analysis of a novel semicircle-shaped parabolic trough solar collector filled with the water–boehmite alumina... 相似文献
9.
10.
S. Nazir 《Physics letters. A》2019,383(16):1977-1982
Interfacial magnetism and magnetic anisotropy constant () in Co/MgO heterostructure have been studied using ab-initio density functional calculations. It is found that interfacial Co spin magnetic moment shows a strong interdependence on Co-O bond lengths and a reasonable spin-polarization of ~80% is established as a function of Co layers. Our results revealed a saturated positive (out-of-plane) of +2.80 mJ/m2 at ≥12 Co layers (~1.6 nm Co thickness), which is associated with orbital magnetic moment difference in [100] and [001] direction along with a strong hybridization between and orbitals through orbital angular momentum operator . Furthermore, it is shown that the magnitude almost remains constant and weakens in the case of under- and over-oxidations in the interfacial MgO and Co layers, respectively. Interestingly, improved for oxygen migrated interface due to enhanced and orbitals coupling. The disordered interfaces stability is checked by analyzing the formation energy. Hence, the present findings disclose that the higher Co thickness in ordered Co/MgO structure supports to out-of-plane [001] (positive) , which could be useful for its technological implementation in high-density magnetic data storage devices with high thermal stability. 相似文献