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121.
We report on a combination of magnetic solid-phase extraction and spectrophotometric determination of bromate. Cetyltrimethylammonium ion was adsorbed on the surface of phenyl-functionalized silica-coated Fe3O4 nanoparticles (Ph-SiO2@Fe3O4), and these materials served as the sorbent. The effects of surfactant and amount of sorbent, the composition of the desorption solution, the extraction time and temperature were optimized. Under optimized conditions, an enrichment factor of 12 was achieved, and the relative standard deviation is 2.9 % (for n?=?5). The calibration plot covers the 1–50 ng mL?1 range with reasonable linearity (r 2?>?0.998); and the limit of detection is 0.5 ng mL?1. The method is not interfered by ionic compounds commonly found in environmental water samples. It was successfully applied to the determination of bromate in spiked water samples. Figure
Extraction of bromate ions using surfactant-coated phenyl functionalized Fe3O4 magnetic nanoparticles followed by spectrophotometric detection. 相似文献
122.
Anwar A Gu M Brady S Qamar L Behbakht K Shellman YG Agarwal R Norris DA Horwitz LD Fujita M 《Photochemistry and photobiology》2008,84(2):477-483
UVB exposure of skin results in various biologic responses either through direct or indirect damage to DNA and non-DNA cellular targets via the formation of free radicals, reactive oxygen species (ROS) and inflammation. Bucillamine [N-(2-mercapto-2-methylpropionyl)-l-cysteine] is a cysteine-derived compound that can replenish endogenous glutathione due to its two donatable thiol groups, and functions as an antioxidant. In this study, we investigated the effects of bucillamine on UVB-induced photodamage using the SKH-1 hairless mouse model. We have demonstrated that UVB exposure (two consecutive doses, 230 mJ cm(-2)) on the dorsal skin of SKH-1 mice induced inflammatory responses (edema, erythema, dermal infiltration of leukocytes, dilated blood vessels) and p53 activation as early as 6 h after the last UVB exposure. Bucillamine pretreatment (20 mg kg(-1) of body weight, administered subcutaneously) markedly attenuated UVB-mediated inflammatory responses and p53 activation. We have also demonstrated that the stabilization and upregulation of p53 by UVB correlated with phosphorylation of Ser-15 and Ser-20 residues of p53 protein and that bucillamine pretreatment attenuated this effect. We propose that bucillamine has potential to be effective as a photoprotective agent for the management of pathologic conditions elicited by UV exposure. 相似文献
123.
S. Tangestaninejad M. Moghadam V. Mirkhani I. Mohammadpoor-Baltork K. Ghani 《Journal of the Iranian Chemical Society》2008,5(1):S71-S79
A new heterogeneous catalyst prepared by immobilization of MO2(acac)2 on Mobil Catalytic Material, MCM-41, is reported. This catalyst, MoO2(acac)2-MCM-41, was successfully applied for efficient epoxidation of olefins with tert-BuOOH in 1,2-dichloroethane as solvent. The catalyst was characterized by elemental analysis, FT-IR, UV-Vis, X-ray diffraction (XRD), and scanning electron microscopy (SEM). This catalyst can be reused several times without significant loss of its catalytic activity. 相似文献
124.
This study reports on two types of glutamate sensors based on chitosan, i) heterogeneous membrane and ii) coated wire (CWE). The linearity ranges are: i) membrane, 1.0×10?5 to 1.0×10?1 M and ii) CWE, 1.0×10?5 to 1.0×10?3 M. The LODs, and pH ranges are i) membrane, 5.0×10?6 M and 4–8 and ii) CWE, 1.0×10?5 M and 3–5, respectively. The presence of ionic species normally found in foodstuffs did not interfere in both electrodes. Interference in CWE was minimized by prior dilution of the sample. The CWE was further investigated for on‐line analysis. The material for proposed electrodes was cheaper and environmental friendly. Hence, they were suggested as alternative tools for the analysis of glutamate. 相似文献
125.
Farook Ahmad Fook Cheong Chow Yah Wen Ho Yew Siang Chin Andreas Christenson Martina Bainbridge Ahmad Pauzi Md Yusof Sulaiman Ab Ghani 《Electroanalysis》2008,20(9):1008-1015
Monitoring of glucose in subcutaneous and brain striatum have been extensively studied in the past. While biocompatibility was one of the limitations, others included the messy measuring equipments preclude monitoring in a complex environment. This study tried to establish an amperometric measurement of glucose in pre‐ and post‐insulin‐administration on diabetic and hyperglycemia rats via wireless. The results have indicated that the wireless sensing kit used was capable of monitoring glucose in both subcutaneous and brain. The physiological data have also shown a new insight on the fabrication of implantable glucose sensors. 相似文献
126.
Al-Taweel AM Perveen S El-Shafae AM Fawzy GA Malik A Afza N Iqbal L Latif M 《Molecules (Basel, Switzerland)》2012,17(3):2675-2682
Nine compounds have been isolated for the first time from Celtis africana, namely trans-N-coumaroyltyramine (1), trans-N-feruloyltyramine (2), trans-N-caffeoyltyramine (3), lauric acid (4), oleic acid (5), palmitic acid (6), lupeol (7), β-sitosterol (8) and oleanolic acid (9), respectively. Their structures have been elucidated by different spectroscopic techniques. The isolated compounds were screened for their antioxidant, anti-inflammatory and acetylcholinestrease enzyme inhibitory activities. Compounds 1-3 showed significant antioxidant and anti-inflammatory activities and weak to moderate acetylcholinestrease enzyme inhibition activity. 相似文献
127.
Lubna Shaheen 《Semigroup Forum》2012,85(2):337-360
This paper discusses necessary and sufficient conditions on a monoid S, such that a class of left S-acts is first order axiomatisable. Such questions have previously been considered by Bulman-Fleming, Gould, Stepanova and others. Let $\mathcal{C}$ be a class of embeddings of right S-acts. A left S-act B is $\mathcal{C}$ -flat if tensoring with B preserves the embeddings in $\mathcal{C}$ . We find two sets (depending on a property of $\mathcal{C}$ ) of necessary and sufficient conditions on S such that the class of all $\mathcal{C}$ -flat left S-acts is axiomatisable. These results are similar to the ??replacement tossings?? results of Gould and Shaheen for S-posets. Further, we show how to axiomatise some classes using both replacement tossings and interpolation conditions, thus throwing some light on the former technique. 相似文献