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The adsorption mechanism of Cr(VI) onto different α-Fe2O3 crystal facets is chemisorption process through outer surface of doubly and triply coordinated hydroxyl groups.<br><br>Display Omitted<br>• 3D hierarchical α-Fe2O3 nanoparticles with different planes predominantly exposed were synthesized. • The Cr(VI) removal ability reach to 34.4 mg/g by flower-like α-Fe2O3 particles with (0 0 1) plane exposed. • The coordination between Cr(VI) and special doubly coordinated hydroxyl groups plays important role for adsorption.<br>Two kinds of 3D hierarchical α-Fe2O3 nanoparticles, flower-like structure with the (0 0 1) plane predominantly exposed on petals and urchin-like structure with nanorods grown along [0 0 1] direction, have been synthesized under the influence of glycerol by a facile hydrothermal method. It is proposed that the Fe(III)-glycerol micro-reaction units that selectively adsorb to (0 0 1) or other planes result in different morphologies. The adsorption of Cr(VI) from aqueous solution onto these α-Fe2O3 nanoparticles showed that the removal efficiency up to 98.5% and 88.8% in 25 mg/L Cr(VI) solution, and the adsorption capacity reaches to 34.4 mg/g and 26.0 mg/g without pH adjustment. The adsorption kinetic is well described by the pseudo-second-order model and the Cr(VI) adsorption on the adsorbent agrees well with the Langmuir model. Lower surface areas and more excellent adsorption property associates with the chemisorption of Cr(VI) onto α-Fe2O3 (0 0 1), which is achieved by coordination between Cr(VI) and doubly or triply coordinated hydroxyl groups on α-Fe2O3 surface.
• MnFe2O4/MoS2 nanocomposites were prepared by a sonochemical method. • MoS2 nanosheets were exfoliated and decorated homogeneously with MnFe2O4 nanoparticles. • Mesoporous structure with specific surface area of 97.16 m2/g. • Superparamagnetic behavior with saturation magnetization of 37.4 Am2/kg.<br>This study established a facile one-step strategy to anchor MnFe2O4 nanoparticles on the surface of MoS2 nanosheets in a controlled manner. The as-prepared MnFe2O4/MoS2 nanocomposites were investigated by TEM, XRD, XPS, Raman, BET and VSM in detail. The MnFe2O4 nanoparticles with an average particle size of 26 nm were densely and uniformly decorated on MoS2 nanosheets, and consequently, both the aggregation of MnFe2O4 nanoparticles and restacking of MoS2 nanosheets were effectively prevented. More importantly, the MnFe2O4/MoS2 nanocomposites exhibited high specific surface area, typical superparamagnetic behavior and excellent solution dispersion, showing a great potential for biomedical applications in the fields of magnetic resonance imaging, targeted drug delivery and tumor hyperthermia.
Traditional Tibetan medicine provides an abundant source of knowledge on human ailments and their treatment. As such, it is necessary to explore their active single compounds used to treat these ailments to discover lead compounds with good pharmacologic properties. In this present work, animal medicine, Osteon Myospalacem Baileyi extracts have been separated using a two-dimensional preparative chromatographic method to obtain single compounds with high purity as part of the following pharmacological research. Five high-purity cyclic dipeptides from chromatography work were studied for their dihydroorotate dehydrogenase inhibitory activity on recombinant human dihydroorotate dehydrogenase enzyme and compound Fr. 1-4 was found to contain satisfying inhibition activity. The molecular modeling study suggests that the active compound Fr. 1-4 may have a teriflunomide-like binding mode. Then, the energy decomposition study suggests that the hydrogen bond between Fr. 1-4 and Arg136 can improve the binding mode to indirectly increase the van der Waals binding energy. All the results above together come to the conclusion that the 2, 5-diketopiperazine structure group can interact with the polar residues well in the active pocket using electrostatic power. If some proper hydrophobic groups can be added to the sides of the 2, 5-diketopiperazine group, it is believed that better 2, 5-diketopiperazine dihydroorotate dehydrogenase inhibitors will be found in the future.
Abstract Lancea tibetica is an important traditional Tibetan medicinal plant that grows on the Qinghai-Tibet Plateau with great development potential in pharmaceutical industry. In this study, a combinative method using HPLC-DPPH and two-dimensional liquid chromatography has been developed to identify and separate antioxidants from Lancea tibetica. Under the target-guidance of HPLC-DPPH experiment, three antioxidant fractions from Lancea tibetica were recognized. Then, separation of the three fractions using two-dimensional semi-preparation liquid chromatography led to seven phenylpropanoids: (+)-pinoresinol-β-D-glucoside (1), isoacteoside (2), acteoside (3), tibeticoside (4),epipinoresinol (5), anthelminthicol (6) and phillygenol (7). As a result, seven major antioxidants in Lancea tibetica were isolated with more than 96% purity. Furthermore, in vitro bioassay against DPPH revealed compounds 1 – 7 with IC 50 values ranging from 6.16 ± 0.08 to 25.09 ± 0.11 (μM) and compounds 1 , 2 and 3 showed activities stronger than the two reference antioxidants (vitamin C, rutin), with IC 50 values of 6.16 ± 0.08, 8.93 ± 0.06 and 7.98 ± 0.05 (μM), respectively. Results of the present study indicated that the method was an efficient technique to systematically screen and isolate antioxidants from medicine crops. Graphical abstract Unlabelled Image Highlights • A novel screen and separation method for purification of antioxidants directly. • Seven antioxidants isolated from Lancea tibetica bioactivity-guided. • Isolated antioxidants with IC 50 values from 6.16 ± 0.08 to 25.09 ± 0.11 (μM). • The first report on antioxidant capacity of the compounds from Lancea tibetica.