نتایج جستجو برای: flash chromatography
تعداد نتایج: 124038 فیلتر نتایج به سال:
Flash sintering as a new sintering method for sintering of ceramic materials has been studied and effect of various parameter such as flash current density, time of flash and contact paste on properties of flash sintered 8YSZ samples has been investigated. Results showed it is possible to achieve high density in shorter time and lower temperature than conventional sintering methods. Samples cou...
We recently introduced a method (Griffin, B. A.; Adams, S. R.; Tsien, R. Y. Science 1998, 281, 269-272 and Griffin, B. A.; Adams, S. R.; Jones, J.; Tsien, R. Y. Methods Enzymol. 2000, 327, 565-578) for site-specific fluorescent labeling of recombinant proteins in living cells. The sequence Cys-Cys-Xaa-Xaa-Cys-Cys, where Xaa is an noncysteine amino acid, is genetically fused to or inserted withi...
INTRODUCTION The diversity of structure and, particularly, stereochemical variation of the dehydropyrrolizidine alkaloids can present challenges for analysis and the isolation of pure compounds for the preparation of analytical standards and for toxicology studies. OBJECTIVE To investigate methods for the separation of gram-scale quantities of the epimeric dehydropyrrolizidine alkaloids lycop...
n-Alkanes, polycyclic aromatic hydrocarbons (PAHs), n-alkanals, n-alkan-2-ones, long-chain alkenones, oxy-PAHs, n-alkanols, sterols and free alkanoic acids have been reliably determined in various environmental matrices by using one-step flash chromatography compound class fractionation and subsequent gas chromatography (GC)–MS and/or GC–flame ionization detection analysis. The obtained recover...
Borututu (Cochlospermum angolensis) is an African tree whose bark has recently emerged as a herbal dietary supplement with claims for antioxidant activity. In order to substantiate the claimed activity of borututu supplements, we performed an activity-guided fractionation of the total extract utilizing a 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay. Subsequent flash and ce...
H and C NMR spectra were recorded with Bruker DPX-400, AVANCE-400 and DRX-500. The numbering of the protons relate to the numbering chosen in Fig. 1. High resolution mass spectra were obtained with a Micromass LCT via loop-mode injection from a Waters (Alliance 2695) HPLC system. Alternatively a Micromass Q-TOF in combination with a Waters Aquity Ultraperformance LC system was employed. Ionizat...
The components of the essential oil from the roots of Alangium salviifolium were analyzed by capillary gas chromatography-mass spectrometry (GC-MS). Ninety compounds, representing 74.5% of the total oil, were identified; the main components of the oil were epi-α-cadinol, followed by trans-2-hydroxycalamenene, cadalene, and cadina-4,10(15)-dien-3-one. A further unknown component comprised 5.5% o...
Reagents were obtained from commercial suppliers and used as received. Lipase preparation PSIm was purchased from Amano Enzyme Inc. The other lipases were purchased from Sigma-Aldrich. 1H-NMR and 13C-NMR data were recorded on a Bruker Avance 400 (100) MHz and/or a Bruker Avance 500 (125) MHz, respectively. Chemical shifts are reported as δ values (ppm) with CDCl3 (1H-NMR δ 7.26, 13C-NMR δ 77.16...
Arctigenin was successfully isolated and purified from the crude extract of Saussurea medusa Maxim. by automatic flash preparation chromatography (AFPC). Chromatographic separation was performed with a gradient elution of (A) petroleum ether and (B) acetone. The qualitative analysis was accomplished with thin layer chromatography (TLC) under the following conditions: petroleum etheracetone (5:3...
hot flash is among the most common complaints of menopausal women, affecting their career, social activities and quality of life. this study aimed to investigate the effects of valerian on hot flashes in menopausal women. in this double blind clinical trial, 68 menopausal women with the chief complaint of hot flash were enrolled using sampling at hand and were randomly divided into drug and pla...
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