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R. Ediati W. Aulia B.A. Nikmatin A.R.P. Hidayat U.M. Fitriana C. Muarifah D.O. Sulistiono F. Martak D. Prasetyoko 《Materials Today Chemistry》2021
UiO-66 and chitosan/UiO-66 composites were successfully synthesized by varying the mass addition of chitosan which were 0%, 2.5%, 5%, 10%, and 20% of the mass of UiO-66, denoted as UiO-66, Cs(2.5)/UiO-66, Cs(5)/UiO-66, Cs(10)/UiO-66, and Cs(20)/UiO-66, respectively. UiO-66 was modified with chitosan using the impregnation process. The X-ray diffraction patterns of the synthesized materials showed characteristic peaks at 2θ of 7.25° and 8.39°, which matched to that of the reported UiO-66. In addition, the Fourier transform infrared spectroscopy spectra of the materials showed absorption bands at the same wavenumber as UiO-66 and chitosan previously reported. The surface morphology of UiO-66 observed from scanning electron microscopy images was in the form of agglomerated small cube particles, where the smaller particles were observed for Cs(10)/UiO-66. From the N2 adsorption isotherms, it was found that the Brunauer-Emmett-Teller surface areas of UiO-66, Cs(5)/UiO-66, and Cs(10)/UiO-66 materials were 825.7 m2/g, 835.4 m2/g, and 882.2 m2/g, respectively. The results of the study on adsorption of methyl orange in aqueous solutions showed that Cs(5)/UiO-66 had the highest adsorption capacity of 370.37 mg/g and followed the pseudo–second-order adsorption kinetic with a Langmuir isotherm model. 相似文献
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Shamsa Munir Afzal Shah Abdur Rauf Amin Badshah Hidayat Hussain Zia-ur-Rehman Zahoor Ahmad 《Comptes Rendus Chimie》2013,16(12):1140-1146
The present work reports the redox mechanism of 5-hydroxynaphthalene-1,4-dione (HND), commonly known as juglone, in buffered aqueous media having 50% of ethanol. HND followed different mechanistic routes depending upon the pH of the media and more than one pKa were evaluated from the changes in the slope of the Ep vs. pH plot. The change of pH from acidic to neutral conditions was found to switch the mechanism from CEC to EE mechanism. Pulse techniques were utilized to determine the number of electrons involved in the oxidation and/or the reduction step and to ensure the nature of the redox process. Based upon the obtained results, an electrode reaction mechanism was proposed. Computational studies of HND supported the experimental results. UV-Visible spectroscopy was also employed for the detailed characterization of the compound in a wide range of pH and for the determination of its pKa. 相似文献
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Ahmad VU Hussain J Hussain H Farooq U Farmanullah Lodhi MA Choudhary MI 《Natural product research》2005,19(3):267-274
Two new myrsinol-type diterpene polyesters 3,5,13,17-tetra-O-acetyl-7-O-benzoyl-15-hydroxymyrsinol (1) and 3,5,13,17-tetra-O-acetyl-7-O-butanoyl-13-hydroxymyrsinol (2), with a tricyclic carbon skeleton have been isolated from Euphorbia decipiens Boiss. & Buhse. The structure elucidation of the isolated compounds was based primarily on HREIMS, EIMS, IR, UV, ID-, and 2D-NMR analyses, including COSY, HMQC, HMBC, and NOESY correlations. Compounds 1 and 2 also showed activity against urease enzyme. 相似文献
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Yemele Bouberte M Krohn K Hussain H Dongo E Schulz B Hu Q 《Natural product research》2006,20(9):842-849
Tithoniamarin (1), a new isocoumarin dimer and a new ceramide, named tithoniamide (2a), have been isolated from Tithonia diversifolia, in addition to the known beta-sitosterol and beta-sitosterol glucopyranoside. The structures were elucidated on the basis of spectroscopic and chemical evidence. Preliminary studies showed that 1 has antifungal and herbicidal activities against Microbotryum violaceum and Chlorella fusca. 相似文献
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A simple and low-cost amperometric sensor for amines has been developed using a cobalt wire electrode working in alkaline solution. The sensor may be used as a detector for high-performance liquid chromatography (HPLC) that avoids the need for derivatization or post-column reaction. Experimental conditions for flow injection analysis (FIA) and HPLC separation, including the applied potential, pH and concentrations of organic modifier and carrier solution, were optimized. A cobalt wire electrode, in the constant potential amperometric mode, gives an excellent response toward amines in ion-exclusion chromatography in unbuffered solution. The sensitivities of the detection and separation of amines on the column are affected by flow rate, the concentration of the mobile phase and the concentration of organic solvent in the mobile phase, whereas the applied potential only affects the sensitivity of the detector. A cobalt electrode is more sensitive than a copper electrode, and comparable in sensitivity to a UV detector for most amines tested. The detection sensitivity is comparable to that obtained with GC methods, but the procedures are far simpler. The detection limits of the order of nanomoles obtained under the chromatographic conditions used offer an alternative for the determination of amines in a variety of matrices, such as in environmental, biomedical and pharmaceutical samples. 相似文献
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Fansheng Ning Heng Zhu Huijiao Yan Jiguo Liu Shahid Aziz Hidayat Hussain Xiangyun Song Lei Xie Zhaoqing Meng Guiyun Cao Daijie Wang 《Journal of separation science》2023,46(16):2300053
In this work, the preparative separation of quinolyridine alkaloids from seeds of T. lanceolata by conventional and pH-zone-refining counter-current chromatography. Traditional counter-current chromatography separation was performed by a flow-rate changing strategy with a solvent system of ethyl acetate-n-butanol-water (1:9:10, v/v) and 200 mg sample loading. Meanwhile, the pH-zone-refining mode was adopted for separating 2.0 g crude alkaloid extracts with the chloroform-methanol-water (4:3:3, v/v) solvent system using the stationary and mobile phases of 40 mM hydrochloric acid and 10 mM triethylamine. Finally, six compounds, including N-formylcytisine (two conformers) ( 1 ), N-acetycytisine (two conformers) ( 2 ), (-)-cytisine ( 3 ), 13-β-hydroxylthermopsine ( 4 ), N-methylcytisine ( 5 ), and thermopsine ( 6 ) were successfully obtained in the two counter-current chromatography modes with the purities over 96.5%. Moreover, we adopted nuclear magnetic resonance and mass spectrometry for structural characterization. Based on the obtained findings, the pH-zone-refining mode was the efficient method to separate quinolyridine alkaloids relative to the traditional mode. 相似文献
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Wenya Ma Iftikhar Ali Yali Li Hidayat Hussain Huanzhu Zhao Xuan Sun Lei Xie Li Cui Daijie Wang 《Molecules (Basel, Switzerland)》2021,26(19)
Toddalia asiatica (L.) Lam. (Rutaceae) has shown a broad spectrum of biological properties, such as anti-inflammatory, antioxidant, antimicrobial, anti-HIV, and anticancer properties. The present study is concerned with the separation of the main components with broad partition coefficients (KD values) from T. asiatica, using linear gradient high-speed counter-current chromatography (LGCCC) combined with an off-line two-dimensional (2D) mode. Similar to the binary gradient HPLC, the LGCCC mode is operated by the adjustment of the proportion between the mobile phase of 5:5:1:9 (v/v) (pump A) and 5:5:4.5:5.5 (v/v) (pump B) in an n-hexane/ethyl acetate/methanol/water solvent system. The off-line 2D-CCC mode was used in this study for the secondary separation of two similar KD value compounds with n-hexane/ethyl acetate/methanol/water (5:5:4:6, v/v). Notably, six coumarins, namely, tomentin (1), toddalolactone (2), 5,7,8-trimethoxycoumarin (3), mexoticin (4), isopimpinellin (5), and toddanone (6), were efficiently separated. The structures of the pure compounds were elucidated by spectral techniques and compared with the literature. 相似文献
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Nilufar Z. Mamadalieva Fadia S. Youssef Hidayat Hussain Gokhan Zengin Adriano Mollica Nawal M. Al Musayeib Mohamed L. Ashour Bernhard Westermann Ludger A. Wessjohann 《Molecules (Basel, Switzerland)》2021,26(21)
The antioxidant and enzyme inhibitory potential of fifteen cycloartane-type triterpenes’ potentials were investigated using different assays. In the phosphomolybdenum method, cycloalpioside D (6) (4.05 mmol TEs/g) showed the highest activity. In 1,1-diphenyl-2-picrylhydrazyl (DPPH*) radical and 2,2′-azino-bis(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) cation radical scavenging assays, cycloorbicoside A-7-monoacetate (2) (5.03 mg TE/g) and cycloorbicoside B (10) (10.60 mg TE/g) displayed the highest activities, respectively. Oleanolic acid (14) (51.45 mg TE/g) and 3-O-β-d-xylopyranoside-(23R,24S)-16β,23;16α,24-diepoxycycloart-25(26)-en-3β,7β-diol 7-monoacetate (4) (13.25 mg TE/g) revealed the highest reducing power in cupric ion-reducing activity (CUPRAC) and ferric-reducing antioxidant power (FRAP) assays, respectively. In metal-chelating activity on ferrous ions, compound 2 displayed the highest activity estimated by 41.00 mg EDTAE/g (EDTA equivalents/g). The tested triterpenes showed promising AChE and BChE inhibitory potential with 3-O-β-d-xylopyranoside-(23R,24S)-16β,23;16α,24-diepoxycycloart-25(26)-en-3β,7β-diol 2′,3′,4′,7-tetraacetate (3), exhibiting the highest inhibitory activity as estimated from 5.64 and 5.19 mg GALAE/g (galantamine equivalent/g), respectively. Compound 2 displayed the most potent tyrosinase inhibitory activity (113.24 mg KAE/g (mg kojic acid equivalent/g)). Regarding α-amylase and α-glucosidase inhibition, 3-O-β-d-xylopyranoside-(23R,24S)-16β,23;16α,24-diepoxycycloart-25(26)-en-3β,7β-diol (5) (0.55 mmol ACAE/g) and compound 3 (25.18 mmol ACAE/g) exerted the highest activities, respectively. In silico studies focused on compounds 2, 6, and 7 as inhibitors of tyrosinase revealed that compound 2 displayed a good ranking score (−7.069 kcal/mole) and also that the ΔG free-binding energy was the highest among the three selected compounds. From the ADMET/TOPKAT prediction, it can be concluded that compounds 4 and 5 displayed the best pharmacokinetic and pharmacodynamic behavior, with considerable activity in most of the examined assays. 相似文献
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A magnetic resonance sequence for high-resolution imaging of coronary arteries in a very short acquisition time is presented. The technique is based on fast low-angle shot and uses fat saturation and magnetization transfer contrast prepulses to improve image contrast. GeneRalized Autocalibrating Partially Parallel Acquisitions (GRAPPA) is implemented to shorten acquisition time. The sequence was tested on a moving anthropomorphic silicone heart phantom where the coronary arteries were filled with a gadolinium contrast agent solution, and imaging was performed at varying heart rates using GRAPPA. The clinical relevance of the phantom was validated by comparing the myocardial relaxation times of the phantom's homogeneous silicone cardiac wall to those of humans. Signal-to-noise ratio and contrast-to-noise ratio were higher when parallel imaging was used, possibly benefiting from the acquisition of one partition per heartbeat. Another advantage of parallel imaging for visualizing the coronary arteries is that the entire heart can be imaged within a few breath-holds. 相似文献