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91.
Gaber Hashem Gaber Ahmed Rosana Badía Laíño Josefa Angela García Calzón Marta Elena Díaz García 《Mikrochimica acta》2014,181(9-10):941-948
We describe the synthesis of ß-cyclodextrin modified magnetic nanoparticles (CD-mNPs) as a material for solid-phase extraction of the cancer biomarker 5-hydroxy-indole-3-acetic acid (5-HIAA) from urine. The CD-mNPs were characterized by TEM, FTIR, and XRD, and the kinetics and adsorption isotherms were studied. The strong interaction between the CD-mNPs and 5-HIAA is the main driving force for recognition and extraction, while the magnetic core of the NPs allows their separation from the sample matrix. Recovery of 5-HIAA from the adsorbent using an adequate solvent regenerated the adsorbent for further use. 5-HIAA was then quantified by fluorometry of its complex with ß-CD. The method works in the 1?×?10?7 to 1?×?10?5 mol L?1 (R2 0.9982–0.9996) concentration range, and the limits of detection (3σ) and quantification (10 σ) of the method are 1.2?×?10?8 mol L?1 and 4.01?×?10?8 mol L?1 5-HIAA, respectively. The recovery of 5-HIAA from urine samples spiked with 5-HIAA in three concentrations (1.4?×?10?6, 4.50?×?10?6 and 1.0?×?10?5 mol L?1) are within 63?±?3 %. Figure
Cyclodextrin functional magnetic nanoparticles as sorbents for separation of 5-hydroxy-3-indole acetic acid and its fluorescence determination after released with methanol. 相似文献
92.
M. M. Aly A. M. Fahmy A. M. Gaber 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4):253-258
Abstract Thermolysis of N-benzoyl-N′-phenylthiourea (BPTU) on heating in air at 230°C gives NH3, H2S, benzaldehyde, benzil, aniline, azobenzene, benzamide, benzanilide, phenylisothiocyanate, phenyl-cyanamide, thiocarbanilide and benzoylisothiocyanate, whereas thermolysis of N-benzoy1-N′-benzylthiourea (BBTU) affords NH3, H2S, benzaldehyde, benzil, toluene, bibenzyl, stilbene, benzamide, cyanamide, benzylisothiocyanate, benzoylthiourea and benzoylisothiocyanate. Thermolysis of N-benzoyl-N′-α-naphthylthiourea (BNTU) under the same conditions gives NH3, H2S. benzaldehyde, benzil, benzamide, α-naphthylisothiocyanate, α-naphthanilide, α-naphthylcyanamide. benzoylisothiocyanate, α-naphthylamine and N,N′-di-α,α′-naphthylthiourea. Analogous results were also obtained on photolysis of (BFTU), (BBTU) and (BNTU) with the exception of NH3, and the photodegradation products of phenylthiourea, benzylthiourea and a-naphthylthiourea respectively. The main feature of these pyrolyses is the homolysis of the amide and thioamide bonds providing free radicals that undergo different reactions involving H-abstraction, dimerization, coupling, fragmentation, rearrangement and disproportionation to yield the identified products. 相似文献
93.
JPC – Journal of Planar Chromatography – Modern TLC - A thin-layer chromatographic system comprising of silica gel as stationary phase and 1.0% aqueous urea solution as mobile phase (pH... 相似文献
94.
Facile Route to Novel Pyrazolo[3,4‐d]pyrimidine,Imidazo[1,2‐b] pyrazole,Pyrazolo[3,4‐d][1,2,3]triazine,Pyrazolo[1,5‐c][1,3,5]triazine and Pyrazolo[1,5‐c][1,3,5]thiadiazine Derivatives 下载免费PDF全文
Samir Bondock Abd El‐Gaber Tarhoni Ahmed A. Fadda 《Journal of heterocyclic chemistry》2015,52(2):346-351
A regioselective synthesis of novel pyrazolo[3,4‐d]pyrimidines, imidazo[1,2‐b]pyrazoles, pyrazolo[3,4‐d][1,2,3]triazine, pyrazolo[1,5‐c][1,3,5]triazine and pyrazolo[1,5‐c][1,3,5]thiadiazine incorporating a thiazole moiety was described via the reactions of the versatile, readily accessible 5‐amino‐3‐(phenylamino)‐N‐(4‐phenylthiazol‐2‐yl)‐1H‐pyrazole‐4‐carboxamide ( 1 ) with each of DMF‐DMA, phenylisothiocyanate, chloroacetyl chloride, phenacyl bromide, benzoylisothiocyanate and formalin, respectively. All structures of the newly synthesized compounds were elucidated by elemental analysis and spectral data. 相似文献
95.
Dr. Abdul Khayum Mohammed Dr. Jésus Raya Ajmal Pandikassala Dr. Matthew A. Addicoat Safa Gaber Mohamed Aslam Dr. Liaqat Ali Dr. Sreekumar Kurungot Prof. Dinesh Shetty 《Angewandte Chemie (International ed. in English)》2023,62(29):e202304313
Hydrogen-bonded organic frameworks (HOFs) are ordered supramolecular solid structures, however, nothing much explored as centimetre-scale self-standing films. The fabrication of such crystals comprising self-supported films is challenging due to the limited flexibility and interaction of the crystals, and therefore studies on two-dimensional macrostructures of HOFs are limited to external supports. Herein, we introduce a novel chemical gradient strategy to fabricate a crystal-deposited HOF film on an in situ-formed covalent organic polymer film (Tam-Bdca-CGHOF). The fabricated film showed versatility in chemical bonding along its thickness from covalent to hydrogen-bonded network. The kinetic-controlled Tam-Bdca-CGHOF showed enhanced proton conductivity (8.3×10−5 S cm−1) compared to its rapid kinetic analogue, Tam-Bdca-COP (2.1×10−5 S cm−1), which signifies the advantage of bonding-engineering in the same system. 相似文献
96.
Salwinder Singh Dhaliwal Vivek Sharma Arvind Kumar Shukla Janpriya Kaur Vibha Verma Manmeet Kaur Prabhjot Singh Marian Brestic Ahmed Gaber Akbar Hossain 《Molecules (Basel, Switzerland)》2022,27(11)
Micronutrient deficiency is a major constraint for the growth, yield and nutritional quality of cowpea which results in nutritional disorders in humans. Micronutrients including molybdenum (Mo), iron (Fe) and zinc (Zn) play a pivotal role in crop nutrition, and their role in different metabolic processes in crops has been highlighted. In order to increase the nutritional quality of cowpea, a field experiment was conducted for two years in which the effect of Mo along with iron (Fe) and zinc (Zn) on productivity, nitrogen and micronutrient uptake, root length and the number of nodules in cowpea cultivation was investigated. It was found that the foliar application of Fe and Zn and their interaction with Mo application through seed priming as well as soil application displayed increased yield, nutrient concentration, uptake and growth parameters which helped to enhance the nutritional quality of cowpea for consumption by the human population. The results of the above experiments revealed that among all the treatments, the soil application of Mo combined with the foliar application of 0.5% each of FeSO4·7H2O and ZnSO4·7H2O (M2F3 treatment) enhanced the grain and stover yield of cowpea, exhibiting maximum values of 1402 and 6104.7 kg ha−1, respectively. Again, the M2F3 treatment resulted in higher Zn, Fe and Mo concentrations in the grain (17.07, 109.3 and 30.26 mg kg−1, respectively) and stover (17.99, 132.7 and 31.22 mg kg−1, respectively) of cowpea. Uptake of Zn, Fe and Mo by the grain (25.23, 153.3 and 42.46 g ha−1, respectively) as well as the stover (104.2, 809.9 and 190.6 g ha−1, respectively) was found to be maximum for the M2F3 treatment. The root length (30.5 cm), number of nodules per plant (73.0) and N uptake in grain and stover (55.39 and 46.15 kg ha−1) were also higher for this treatment. Overall, soil application of Mo along with the foliar application of FeSO4·7H2O (0.5%) and ZnSO4·7H2O (0.5%) significantly improved yield outcomes, concentration, uptake, root length, nodules plant−1 and N uptake of cowpea to alleviate the micronutrient deficiency. 相似文献
97.
Michael A. Markowitz David C. Turner Brett D. Martin Bruce P. Gaber 《Applied biochemistry and biotechnology》1997,68(1-2):57-68
Diffusion of antibody protein from hydrogel films and hydrogel encapsulated in a microcapillary was studied. Thin hydrogel
films were formed by crosslinking 6-acryloyl-B-O-methylgalactoside withN,N’-methylene-bis-acrylamide and the diffusive transport of monoclonal antimouse IgG-FITC into and out of the hydrated films was measured.
Diffusion coefficients in 2 and 4% crosslinked hydrogel films were measured. The measured diffusion constants determined for
IgG in both the 2 and 4% hydrogel films were comparable to the free diffusion of IgG in bulk water (D
mean ∼ 10-7cm2/s). In addition, 2% crosslinked hydrogels were prepared in a capillary tube and the transport of antimouse IgG-FITC into
and out of the hydrated hydrogel was measured. Kinetic analysis indicated that the protein transport through the capillary
hydrogel was faster than would be expected for a simple diffusion process. Finally, by utilizing the diffusion of antibody
from the capillary hydrogel, transfer of antibody to a silica surface was demonstrated. A capillary hydrogel loaded with antimouse
IgG-FITC was used to transfer the protein to a silica surface forming a 30-μm spot of antibody, which was imaged using fluorescence
microscopy. These results may lead to the development of a nonlithographic method of patterning antibodies on surfaces for
use in integrated microimmunosensors. 相似文献
98.
Two selected benzoylhydrazones I and II were subjected to thermolysis by reflux at 200 °C. Benzil, benzoic acid, biphenyl, benzanilide together with the corresponding ketones, nitriles and imines were isolated. Similar treatment of the third hydrazone III at 250 °C afforded, in addition to the previous products, bibenzyl, stilbene, and 2-phenylindole. Photolysis of the same hydrazones I-III in acetonitrile gave the previously reported products but in different ratios along with azine derivatives and substituted methanes. A free radical mechanism involving homolysis of the N-N and C-N bonds is suggested, substantiated by trapping of phenyl radical with isoquinoline, to account for the formation of the identified products. 相似文献
99.
Rates of corrosion of low alloy ASTM A213 grade T22 boiler steel were monitored in aerated stagnant 0.50 M HCl solutions at different temperatures (283–303 K) using Tafel extrapolation method and the non-destructive electrochemical frequency modulation (EFM) technique, complemented with XPS examinations. Serine (Ser) was introduced as a corrosion-safe inhibitor. Corrosion rates (in μm y?1) obtained from these two methods was in good agreement. Tafel plots showed that Ser acted mainly as a cathodic-type inhibitor. The inhibition process was attributed to the formation of an adsorbed film on the metal surface that protects the metal against corrosive agents. XPS examinations of the electrode surface confirmed the existence of such adsorbed film. The inhibition efficiency increased with increase in Ser concentration, while it decreased with temperature, suggesting physical adsorption. Activation energies have been calculated in the absence and presence of various concentrations of Ser by measuring the temperature dependence of the corrosion rate obtained from the two methods employed. It was found that the activation energy in the presence of Ser is higher than that in bare HCl solution. The adsorptive behaviour of Ser followed Temkin-type isotherm. The standard free energy of adsorption was estimated to be ?25 kJ mol?1 at 303 K. These results confirmed the occurrence of physical adsorption. 相似文献
100.
Abd El-Aal M. Gaber Hussni A. Muathen Layla A. Taib 《Journal of Analytical and Applied Pyrolysis》2011,91(1):119-124
Thermolysis of N-phenylbenzamide oximes I, II and III (R = Cl, NO2 and OCH3) under nitrogen gives rise to benzimidazoles as the major products (45-52%), in addition to benzonitrile, arylamines, benzoic acid, phenols, benzanilides, 2-phenyl benzoxazoles and carbazoles. In the presence of naphthalene, I gave α- and β-naphthols beside the previous products. Also heating of I under reflux boiling tetralin lead to the formation of 1-hydroxytetralin, α-tetralone and 1,1′-bitetralyl as the major products. The isolated products have been interpreted in the terms of a free radical mechanism involving the homolysis of N-O and/or C-N bonds. 相似文献