A Simple and Efficient Two-Dimensional High-Speed Counter-Current Chromatography Linear Gradient and Isocratic Elution Modes for the Preparative Separation of Coumarins from Roots of Toddalia asiatica (Linn.) Lam.

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 (K_D 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 K_D 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.     

Investigation of the Uptake and Transport of Two Novel Camptothecin Derivatives in Caco-2 Cell Monolayers

Irinotecan and Topotecan are two Camptothecin derivatives (CPTs) whose resistance is associated with the high expression of breast cancer resistance protein (BCRP) and P-glycoprotein (P-gp). To reverse this resistance, two novel CPTs, FL77-28 (7-(3-Fluoro-4-methylphenyl)-10,11-methylenedioxy-20(S)-CPT) and FL77-29 (7-(4-Fluoro-3-methylphenyl)-10,11-methylenedioxy-20(S)-CPT), were synthesized by our group. In this study, the anti-tumor activities of FL77-28, FL77-29, and their parent, FL118 (10,11-methylenedioxy-20(S)-CPT), were evaluated and the results showed that FL77-28 and FL77-29 had stronger anti-tumor activities than FL118. The transport and uptake of FL118, FL77-28, and FL77-29 were investigated in Caco-2 cells for the preliminary prediction of intestinal absorption. The apparent permeability coefficient from apical to basolateral (P_{app AP-BL}) values of FL77-28 and FL77-29 were (2.32 ± 0.04) × 10⁻⁶ cm/s and (2.48 ± 0.18) × 10⁻⁶ cm/s, respectively, suggesting that the compounds had moderate absorption. Since the transport property of FL77-28 was passive diffusion and the efflux ratio (ER) was less than 2, two chemical inhibitors were added to further confirm the involvement of efflux proteins. The results showed that FL77-28 was not a substrate of P-gp or BCRP, but FL77-29 was mediated by P-gp. In conclusion, FL77-28 might be a promising candidate to overcome drug resistance induced by multiple efflux proteins.     

烯碳纤维基能源器件的研究进展

纤维状能源器件的研究极大地推动了可穿戴电子设备的快速发展。烯碳纤维主要包括碳纳米管纤维和石墨烯纤维,其微观组成单元具有独特的碳碳共轭分子形态,宏观结构具有高度可调控性,表现出高的比强度、优良的导电性和导热性、以及良好的机械柔韧性等,被广泛应用于先进能源器件的研究和开发,有效促进了柔性可穿戴电子器件的发展。本文综述了烯碳纤维基能源器件包括能量转换和储能器件等的研究和应用进展,具体介绍了烯碳纤维基太阳能电池、湿气发电机、热电发电机、超级电容器以及电化学电池等的最新成果,重点讨论了烯碳纤维基能源器件的制备方法和可穿戴应用,分析了烯碳纤维基储能及能量转换器件面临的问题和挑战,期望能够为未来高性能纤维基可穿戴能源器件的发展提供有价值的研究思路。     

Ultra-fast screening of free fatty acids in human plasma using ion mobility mass spectrometry

Free fatty acids are involved in many metabolic regulations in the human body. In this work, an ultra-fast screening method was developed for the analysis of free fatty acids using trapped ion mobility spectrometry coupled with mass spectrometry. Thirty-three free fatty acids possessing different unsaturation degrees and different carbon chain lengths were baseline separated and characterized within milliseconds. Saturated, monounsaturated, and polyunsaturated free fatty acids showed different linearities between collision cross-section values and m/z. The establishment of correlations between structures and collision cross-section values provided additional qualitative information and made it possible to determine free fatty acids which were out of the standards pool but possessed the confirmed linearity. The gas-phase separation made the quantitative analysis reliable and repeatable at a much lower time cost than chromatographic methods. The sensitivity was comparable to and even better than the reported results. The method was validated and applied to profiling free fatty acids in human plasma. Saturated free fatty acids abundance in the fasting state was found to be lower than that in the postprandial state, while unsaturated species abundance was found higher. The method was fast and robust with minimum sample pretreatment, so it was promising in the high-throughput screening of free fatty acids.     

An improved RNA isolation method for filamentous fungus Blakeslea trispora rich in polysaccharides

Isolation and purification of biologically active RNA from filamentous fungi is difficult because of the complex cell wall and the high level of polysaccharides which bind to or co-precipitate with RNA. Using benzyl chloride and guanidine thiocyanate, RNA was successfully isolated from Blakeslea trispora in which other RNA extraction methods and commercially available kits failed to deliver suitable results. The RNA isolated by this procedure appears to be relatively pure, as it has a ratio of absorbance at 260/280 nm of 1.8–1.9. The integrity of the RNA was further substantiated by RT-PCR and Northern hybridization, respectively. This procedure should be useful for isolating RNA from other filamentous fungi and, therefore, will serve as an important tool for the molecular analysis of these organisms.     

Microstructure and anti‐ wear and corrosion performances of novel UHMWPE/graphene‐nanosheet composite coatings deposited by flame spraying

Ultra‐high molecular weight polyethylene (UHMWPE)/graphene‐nanosheet (GN, multiple layers of graphene sheets with the thickness of ~5–10 nm) coatings have been deposited by flame spraying. The structure of UHMWPE remained almost intact after the spray processing and addition of GNs resulted in a slightly decreased crystallinity and improved thermal stability of UHMWPE. In addition, the coating containing 1.0 wt.% GNs exhibited a reduction of ~20% in wear rate and 25% in friction coefficient (0.18 versus 0.24). Significantly enhanced anti‐corrosion performances of the UHMWPE–GN coatings were suggested by increased corrosion potential, corrosion current density, and impedance modulus value of the UHMWPE–GN coatings. The very well retained GNs are located mainly at the interfaces between UHMWPE splats and act as bridges connecting the splats, which mainly accounts for the enhanced properties of the composite coatings. The novel UHMWPE–graphene composite coatings show great potential for protecting engineering components for applications against corrosion. Copyright © 2013 John Wiley & Sons, Ltd.     

Synthesis,Crystal Structures,Optical Properties,and Photocurrent Response of Heteroacene Derivatives

Six 5,9,14,18‐tetrathiaheptacene derivatives ( 1 a – 1 f ) were synthesized by using a simple ether–ether exchange reaction and fully characterized. In contrast to the planar conformation usually observed in thiophene‐fused benzene systems, single‐crystal analysis indicates that 7,16‐dipropyl‐5,9,14,18‐tetrathiaheptacene ( 1 a ), 7,16‐diphenyl‐5,9,14,18‐tetrathiaheptacene ( 1 b ), and 7,16‐di(4′‐chlorophenyl)‐5,9,14,18‐tetrathiaheptacene ( 1 c ) adopt chair conformations. The as‐formed dihedral angle between anthracene and the terminal benzene units are 137.258, 137.855, and 134.912° for 1 a , 1 b , and 1 c , respectively, which is close to the theoretical optimization results (128° for 1 b ). Interestingly, the oxidized product of 7,16‐di(trifluoromethylphenyl)‐5,9,14,18‐tetrathiaheptacene ( 1 e ) has a saddle shape, which results in the formation of column‐shaped units in the single crystal. The substituents on the side phenyl group have less effect on their UV/Vis absorption spectra, but a distinct redshift that accounts for the intramolecular charge transfer can be observed in the emission spectra. The electrochemical measurements show that all compounds present two oxidation waves. The photoswitching behavior based on 1 a–1 f was further measured and the experimental results suggest that these heteroacene derivatives are promising semiconductor materials for organic electronics.     

Tribological Studies on Two Novel Borate Esters with Nitrogen-Containing Heterocyclic and Alkanolamide as Multifunctional Additives in Rapeseed Oil

Borate esters have good load carrying capacity and lubricating properties. However, borate esters are susceptible to hydrolyzation, which limits their applications. To improve the hydrolysis resistance of borate esters, nitrogen-containing heterocyclic and alkanolamide were introduced into their structures. Two novel multifunctional borate esters were synthesized, and their tribological properties were evaluated in rapeseed oil. The two novel borate esters showed superior tribological properties, as well as excellent anti-rust, anti-corrosion, and anti-oxidant properties. During friction, the mixed film containing B₂O₃ and nitrogen-containing organic compounds were formed, iron oxide generated on the worn surface, which were important to anti-wear.     

Preparation and characterization of L-glutamic acid-functionalized graphene oxide for adsorption of Pb(II)

An efficient adsorbent (L-Glu/GO) was successfully synthesized by the reaction between L-glutamic acid (L-Glu) and graphene oxide (GO). The structure and morphology of this adsorbent were characterized by FTIR, SEM, XRD, and TGA. The SEM result indicated that the adsorbent was a nanomaterial with a size of about 50–400 nm. The adsorption experiments of various heavy ions on L-Glu/GO demonstrated that the adsorption performance of Pb(II) was better than others. Various variables affecting the adsorption of L-Glu/GO for Pb(II) were systematically explored. The experimental results indicated that the maximum adsorption capacity and equilibrium time of Pb(II) on L-Glu/GO were 513.4 mg g^?1 and 40 minute, respectively. The sorption kinetics and isotherm fitted well with the pseudo-second-order model and Langmuir model, respectively. The sorption mainly was a chemical process. Thermodynamic studies revealed that the adsorption was a spontaneous and exothermic process. The adsorbent could be regenerated with HCl solution. Hence, it was suggested that the L-Glu/GO could be applied in the removal of Pb(II) from wastewaters.     

Secretory Expression and Characterization of Chinese <Emphasis Type="Italic">Narcissus</Emphasis> GNA-Like Lectin in <Emphasis Type="Italic">Pichia pastoris</Emphasis>

Narcissus tazetta lectin (NTL) is a GNA-like lectin, which has a wide potential application in medicine, agriculture, and glycobiology. In the present paper, the codon-optimized ntl gene was transformed into the yeast Pichia pastoris; SDS–PAGE gel and western blotting analysis revealed that the recombinant lectin was expressed successfully in Pichia yeast. The similarity between the recombinant NTL and the native NTL was confirmed by circular dichroism (CD) and hemagglutination assay further. In the 5-L scale fermentator, the protein yield was as high as 1.2 g/L after fermentation for 96 h. In addition, the effect of metal ions (K⁺, Mg²⁺, Ca²⁺, and Cu²⁺), acid, and alkaline on hemagglutinating activity of NTL was tested, which provided biochemical characterizations of the mannose-binding lectin from Chinese Narcissus.