This study aims to investigate whether the in vitro-cultured L. pumila var. alata has higher antioxidant activity than its wild plant. An 8-week-old L. pumila var. alata nodal segment and leaf explants were cultured onto Murashige and Skoog (MS) medium supplemented with various cytokinins (zeatin, kinetin, and 6-benzylaminopurine (BAP)) for shoot multiplication and auxins (2,4-dichlorophenoxyacetic acid (2,4-D) and picloram) for callus induction, respectively. The results showed that 2 mg/L zeatin produced the optimal results for shoot and leaf development, and 0.5 mg/L 2,4-D produced the highest callus induction results (60%). After this, 0.5 mg/L 2,4-D was combined with 0.25 mg/L cytokinins and supplemented to the MS medium. The optimal results for callus induction (100%) with yellowish to greenish and compact texture were obtained using 0.5 mg/L 2,4-D combined with 0.25 mg/L zeatin. Leaves obtained from in vitro plantlets and wild plants as well as callus were extracted and analyzed for their antioxidant activities (DPPH and FRAP methods) and polyphenolic properties (total flavonoid and total phenolic content). When compared with leaf extracts of in vitro plantlets and wild plants of L. pumila var. alata, the callus extract displayed significantly higher antioxidant activities and total phenolic and flavonoid content. Hence, callus culture potentially can be adapted for antioxidant and polyphenolic production to satisfy pharmaceutical and nutraceutical needs while conserving wild L. pumila var. alata.相似文献
Polyelectrolyte multilayers are built up from ionically modified polyphosphazenes by layer-by-layer assembly of a cationic (poly[bis(3-amino-N,N,N-trimethyl-1-propanaminium iodide)phosphazene] (PAZ+) and an anionic poly[bis(lithium carboxylatophenoxy)phosphazene] (PAZ-). In comparison, multilayers of poly(sodium 4-styrenesulfonate) (PSS) and poly(allylamine hydrochloride) (PAH) are investigated. Frequency-dependent conductivity spectra are taken in sandwich geometry at controlled relative humidity. Conductivity spectra of ion-conducting materials generally display a dc plateau at low frequencies and a dispersive regime at higher frequencies. In the present case, the dispersive regime shows a frequency dependence, which is deviating from the typical behavior found in most ion-conducting materials. Dc conductivity values, which can be attributed to long-range ionic transport, are on the order of sigmadc = 10-10-10-7 S.cm-1 and strongly depend on relative humidity. For PAZ+/PAZ- multilayers sigmadc is consistently larger by one decade as compared to PSS/PAH layers, while the humidity dependence is similar, pointing at general mechanisms. A general law of a linear dependence of log(sigmadc) on relative humidity is found over a wide range of humidity and holds for both multilayer systems. This very strong dependence was attributed to variations of the ion mobility with water content, since the water content itself is not drastically dependent on humidity. 相似文献
One-dimensional (1-D) coordination polymer and mononuclear copper(II) complexes, ([Cu(nphen)(asn)]ClO4)n (1) and [Cu(nphen)(gln)(H2O)]ClO4·H2O (2) (nphen = 5-nitro-110-phenanthroline, asn = asparagine, gln = glutamine), have been synthesized and characterized by IR spectroscopy, ESI-MS, CHN analysis, and single-crystal X-ray diffraction. These binary and ternary complexes of copper(II) with nphen, asn, and gln have been investigated using potentiometric methods in 0.1 M KCl aqueous ionic media at 298.2 K. The protonation constants of the ligands and the stability constants of 1 and 2 have been calculated from the potentiometric data using the “BEST” software package. The potentiometric results have been analyzed using the “SPE” software package, and the distribution curves for the copper-containing species have been determined for the ternary systems. The CT-DNA-binding properties of these complexes have been investigated by thermal denaturation measurements and both absorption and emission spectroscopy. Further, the interaction of these complexes with bovine serum albumin (BSA) and human serum albumin (HSA) has been investigated using absorption and emission spectroscopy. The thermodynamic parameters, free energy change (ΔG), enthalpy change (ΔH), and entropy change (ΔS) were calculated by the van’t Hoff equation and discussed. The distances between the serum albumins and 1 and 2 have been obtained according to fluorescence resonance energy transfer (FRET). Conformational changes of serum albumins have been observed from synchronous fluorescence technique. The antimicrobial activity of the complexes has also been tested on some bacteria. The effect of different amino acids on the copper(II) complexes are discussed. 相似文献
The biosorption of radioactive Th(IV) ions in the aqueous solutions onto the modified powdered waste sludge (MPWS) has been examined. In this context, the parameters affecting biosorption of Th(IV) from aqueous solutions has been examined by using MPWS biosorbent in Box Behnken statistical experimental design. The structure of MPWS biosorbent was characterized by using SEM and BET techniques. According to the experimental design results, MPWS and Th(IV) concentrations should be kept high to achieve the maximum efficiency in Th(IV) biosorption. On the other hand, MPWS, which is also used as a biosorbent, is an economical, effective and natural biosorbent.
The first syntheses of four stereoisomeric diaminocyclooctane diols, as well as a chlorocyclooctane aminodiol, are reported. In the first part, photooxygenation of cis,cis-1,3-cyclooctadiene gave a bicyclic endoperoxide, which was reduced with zinc followed by mesylation of the hydroxyl groups. Treatment with sodium azide afforded 1,4- and 1,2-cyclooctene diazides. Oxidation of the double bonds in the isomeric diazides with OsO4, followed by hydrogenation of the azide groups, led to 3,8-diaminocyclooctane-1,2-diol and 3,4-diaminocyclooctane-1,2-diols. In the second part, cis-3,8-diazidocyclooctene was converted into the corresponding epoxide. Stereospecific hydrolysis of the epoxide ring with HCl(g) in methanol, and hydrogenation of the azide groups gave 3,8-diamino-2-chloro-cyclooctan-1-ol. Bromination of the double bond in cyclooctene diacetate, followed by acetate deprotection, azidolysis of the bromides, and hydrogenation of the azide groups resulted in the formation of 2,3-diaminocyclooctane-1,4-diol. 相似文献
Organic dyes are used in many industries, e.g., textile, cosmetics and food. Hence, contamination of organic dyes to water sources is a critical issue. To reduce water pollution by organic dyes, we propose a paper-like adsorbent with a practical and economical production procedure. Subsequently, a flexible adsorbent was produced using a one-step approach by vacuum filtration of graphene oxide (GO) and iron oxide nanoparticles (Fe3O4-NPs) containing dispersion through a membrane and quoted as GO/Fe3O4 paper. For comparison, GO paper was also prepared using the same procedure. Both papers were characterized using UV–VIS absorption spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, electron diffraction X-ray analysis, X-ray photoelectron spectroscopy, and powder X-ray diffraction techniques. At the steady-state conditions, GO/Fe3O4 and GO papers were performed as adsorbent for cationic dyes of methylene blue, neutral red, and anionic dyes of methyl orange and fluorescein. In general, the removal efficiency of GO/Fe3O4 paper was higher than that of GO paper for adsorption of all dyes and this adsorbent revealed satisfactory adsorption properties for cationic dyes when compared to anionic dyes.
A diastereoselective [3 + 2] cycloaddition of N‐aryl substituted maleimides with N,α‐diphenyl nitrone possessing 11‐hydroxyundecyloxy as a flexible substituent was performed. Experimental and comprehensive mechanistic density functional theory studies reveals that intermolecular H‐bonding and steric repulsive interaction predominate exo‐Z and exo‐E cycloaddition transition states, respectively. The reaction proceeded smoothly depending on the reactants and gave a good yield of (syn) cis‐isoxazolidine or (anti) trans‐isoxazolidine as a single diastereomer. 相似文献
The nonlinear optical properties of a phosphate vitreous system [(ZnO)x-(MgO)30-x-(P2 O5)70], where x=8, 10, 15, 18, and 20 mol% synthesized through the melt-quenching technique have been investigated by using the Z-scan technique. In the experiment, a continuous-wave laser with a wavelength of 405 nm was utilized to determine the sign and value of the nonlinear refractive (NLR) index and the absorption coefficient with closed and opened apertures of the Z-scan setup. The NLR index was found to increase with the ZnO concentration in the glass samples by an order of 10-10 cm2·W-1. The real and imaginary parts of the third-order nonlinear susceptibility were calculated by referring to the NLR index (n2) and absorption coefficient (β) of the samples. The value of the third-order nonlinear susceptibility was presented by nonlinear refractive or absorptive behavior of phosphate glasses for proper utilization in nonlinear optical devices. Based on the measurement, the positive sign of the NLR index shows a self-focusing phenomenon. The figures of merit for each sample were calculated to judge the potential of phosphate glasses for application in optical switching. 相似文献