查找使用阿拉丁产品的科研文献

Influence of sulfur source on properties of CuSbS2 particles

Liu Liu,Yijie Zhao,Guowei Zhi,Lihui Cao,Wei Wang,Luanhong Sun,Yuxuan Che

CuSbS2 is a direct p-type semiconductor with a two-dimensional layered structure of orthorhombic system, excellent electrical performance, and a band gap of 1.1–1.5 eV, which has a light absorption coefficient of more than 104cm−1 in the visible light range. CuSbS2 particles were synthesized by microwave irradiation method, and the effects of different sulfur sources on the phase structure, morphology and electrochemical performance of CuSbS2 particles were studied. The results showed that the sample prepared by thiourea as sulfur source was CuSbS2 phase, and the morphology was composed of flower-like microspheres and rod-like particles. However, nanorod-like CuSbS2 particles were obtained using L-cysteine or 3-thiopropionic acid as sulfur sources, and the phase of samples contained CuSbS2 and Sb2S3 phase. Electrochemical tests showed that L-cysteine based CuSbS2 particles had the largest photocurrent response, a photocurrent density of 1.03 μA cm−2 and impedance of 14.66 Ω.

Study on Chiral Nanocomposite for Recognition of DOPA Enantiomers via Square Wave Voltammetry

Dongmei Guo,Peiyao Ran,Cui Chen,Ya Chen,Chunzhi Xuan,Yingzi Fu

An electrochemical sensor was explored for recognizing 3,4-dihydroxyphenylalanine (DOPA) enantiomers based on L-cysteine covalently binding with the multi-walled carbon nanotubes functionalized with 3,4,9,10-perylene tetracarboxylic acid (MWCNTs-PTCA-Cys). Here two different ways of square wave voltammetry (SWV) and cyclic voltammetry (CV) were utilized to investigate the stereospecific interaction between the MWCNTs-PTCA-Cys nanocomposite and DOPA enantiomers. The D-DOPA and L-DOPA exhibited different response in both CV and SWV, in addition, the difference in SWV was more obvious and reached to 264.9 μA, suggesting that the enantiomers could be successfully distinguished by MWCNTs-PTCA-Cys nanocomposite, and the selection of electrochemical technique played an important role in enantioselective recognition. Under the optimum conditions, the detection limits of D-DOPA and L-DOPA were 2.5 μM and 4.6 μM (S/N = 3), respectively, with a linear range of 1.0 × 10−5 M to 5.0 × 10−3 M. This work provided a simple method to recognize and determine DOPA enantiomers with rapid response, excellent recognition ability, high sensitivity and good stability.

David L. Morse to give plenary address on glass at 2013 MRS Fall Meeting

Enantioselective Recognition of L-Lysine by ICT Effect with a Novel Binaphthyl-Based Complex

Shi Tang,Zhaoqin Wei,Jiani Guo,Xiaoxia Sun,Yu Hu

A novel triazole fluorescent sensor was efficiently synthesized using binaphthol as the starting substrate with 85% total end product yield. This chiral fluorescence sensor was proved to have high specific enantioselectivity for lysine. The fluorescence intensity ofR-1was found to increase linearly when the equivalent amount of L-lysine (0–100 eq.) was gradually increased in the system. The fluorescence intensity of L-lysine toR-1was significantly enhanced, accompanied by the red-shift of emission wavelength (389 nm to 411 nm), which was attributed to the enhanced electron transfer within the molecular structure, resulting in anICTeffect, while the fluorescence response of D-lysine showed a decreasing trend. The enantioselective fluorescence enhancement ratio for the maximum fluorescence intensity was 31.27 [ef = |(IL−I0)/(ID−I0)|, 20 eq. Lys], thus it can be seen that this fluorescent probe can be used to identify and distinguish between different configurations of lysine.Keywords:enantioselective recognition;ICT effect;intermolecular hydrogen bond

Extraction of Oil from Flaxseed (Linum usitatissimum L.) Using Enzyme-Assisted Three-Phase Partitioning

Tan Zhi-jian,Yang Zi-zhen,Yi Yong-jian,Wang Hong-ying,Zhou Wan-lai,Li Fen-fang,Wang Chao-yun

In this study, enzyme-assisted three-phase partitioning (EATPP) was used to extract oil from flaxseed. The whole procedure is composed of two parts: the enzymolysis procedure in which the flaxseed was hydrolyzed using an enzyme solution (the influencing parameters such as the type and concentration of enzyme, temperature, and pH were optimized) and three-phase partitioning (TPP), which was conducted by adding salt and t -butanol to the crude flaxseed slurry, resulting in the extraction of flaxseed oil into alcohol-rich upper phase. The concentration of t -butanol, concentration of salt, and the temperature were optimized to maximize the extraction yield. Under optimized conditions of a 49.29 % t- butanol concentration, 30.43 % ammonium sulfate concentration, and 35 °C extraction temperature, a maximum extraction yield of 71.68 % was obtained. This simple and effective EATPP can be used to achieve high extraction yields and oil quality, and thus, it is potential for large-scale oil production.

Elicitors Modulate Young Sandalwood (Santalum album L.) Growth, Heartwood Formation, and Concrete Oil Synthesis

Yuan Li,Xinhua Zhang,Qingwei Cheng,Jaime A. Teixeira da Silva,Lin Fang,Guohua Ma

Five chemical elicitors––6-benzyladenine (BA), ethephon (ETH), methyl jasmonate (MeJA), hydrogen peroxide (H2O2) and calcium chloride (CaCl2)––were used to treat 1- and 5-year-old sandal trees (Santalum albumL.) to assess their effects on growth, heartwood formation and concrete oil synthesis. The results showed that some newly formed branches in stems that were induced by BA and ETH displayed leaf senescence and developed new smaller and light-green leaves. The relative percentage of concrete oil from the heartwood of water-treated trees (0.65%) was significantly lower than that from trees treated with 4 mM H2O2(2.85%) and 4 mM BA (2.75%) within one year. Four mM BA, H2O2and CaCl2induced a significantly higher level of sesquiterpenoids than heartwood treated with 2 mM of these elicitors. Four mM MeJA induced significantly less sesquiterpenoids than heartwood treated with 2 mM MeJA. Morphological, physiological, and chromatographic–spectrometric technologies were integrated to trace the potential function of these exogenously applied chemical elicitors. The results may have important applications and provide a better understanding of the molecular mechanism of heartwood formation and hardening in young sandalwood trees.Keywords:concrete oil;exogenous elicitors;heartwood formation;sandalwood

Patupilone-loaded poly(L-glutamic acid)-graft-methoxy-poly(ethylene glycol) micelle for oncotherapy

Jing Yan,Dawei Zhang,Haiyang Yu,Lili Ma,Mingxiao Deng,Zhaohui Tang,Xuefei Zhang

Glycopolymer modification on physicochemical and biological properties of poly(l-lysine) for gene delivery

Dezhong Zhou,Congxin Li,Yuling Hu,Hao Zhou,Jiatong Chen,Zhengpu Zhang,Tianying Guo

Poly( l -lysine) (PLL) has excellent plasmid DNA (pDNA) condensation capacity. However, the relatively high cytotoxicity and low transfection efficiency limit its application as gene delivery vectors. Here, well-defined glycopolymers are synthesized by reversible addition fragmentation transfer polymerization and grafted onto PLL to improve the gene delivery performance. After glycopolymer modification, PLL shows reduced cytotoxicity. By regulating the glycopolymer length and amino group substitution degree, the glycopolymer modified PLL can condense pDNA with proper strength, protect the condensed pDNA from degradation and release them in time. Transfection with NIH3T3 and HepG2 cells shows that the glycopolymer modified PLL has improved transfection efficiencies. The low cytotoxicity, effective pDNA protection and enhanced transfection efficiencies indicate that glycopolymer modification would be an effective strategy to improve the polycation properties for gene delivery.

Extraction, Characterization, Antioxidant and Hypoglycemic of Pectic Polysaccharides from Cantaloupe (Cucumis melo L.) Peels

Hui Sun,Ruizhan Chen,Fanlei Meng,Helong Bai,Li Tian,Juan Lu,Chunlong Bai,Dongxue Li,Wenjing Wu,Yongtang Wang,Mingze Gong

In this study, microwave extraction (ME) of pectic polysaccharides (M-CPPs) from cantaloupe peels (CPs) is optimized using response surface methodology (RSM) with a Box–Behnken design (BBD). The optimum ME parameters are liquid–solid ratio 26.04 mL g −1 , microwave power 543.04 W, irradiation time 6.38 min, and pH 1.5. Compared heat reflux extraction polysaccharides (H-CPPs), the yield, the contents of neutral sugars (TSC), uronic acids (UAC), total flavonoids (TFC), total phenolics (TPC), sulfate groups (SGC) of M-CPPs increased by 156.06%, 15.33%, 7.27%, 1019.05%, 1.75%, and 57.89%, but the molecular weight (Mw) and degree of esterification (DE) reduced by 29.08% and 24.81%, respectively. M-CPPs exhibit superior antioxidant and hypoglycemic activities than H-CPPs, which may be attributed to its higher UAC, TFC and SGC, lower Mw, and DE. There is almost no change in the monosaccharide types of isolated polysaccharides, only a change in molar ratio. Results proved that ME is an efficient technique for the extraction and modification of pectic polysaccharides (CPPs) from CPs with high yield, strong antioxidant, and hypoglycemic activities for applications in medical and food industries.

Structural Elucidation and Antioxidant Activities of a Neutral Polysaccharide From Arecanut (Areca catechu L.)

Ji Xiaolong,Guo Jianhang,Pan Feibing,Kuang Fengjun,Chen Haiming,Guo Xudan,Liu Yanqi

A novel neutral polysaccharide designated as PAP1b was isolated from Areca catechu L. by hot water extraction, ethanol precipitation, and column chromatography. PAP1b was mainly composed of mannose, galactose, xylose, and arabinose in a ratio of 4.1:3.3:0.9:1.7, with an average molecular weight of 37.3 kDa. Structural characterization indicated that the backbone of PAP1b appeared to be composed mainly of → 6-β-Manp-(1 →, → 4)-α-Galp-(1 → and → 3,6)-β-Manp-(1 →) residues with some branches, and terminal of (1 →)-linked-β-Manp residues. The results of bioactivity experiments showed that PAP1b had antioxidant in vitro, esspecially on scavenging DPPH and hydroxyl radicals. Therefore, the polysaccharide from Areca catechu L. could be used as a potential antioxidant in functional food.

Leaf extract from Vitis vinifera L. reduces high fat diet-induced obesity in mice

Li Meng,Yuehua Jiao,Xiaohong Zhou,Cong Liang,Kexin Yan,Ye Zhao,Xiujie Deng,Xue Han,Yanyan Yang,Hanmin Liu,Pimin Gong,Lanwei Zhang

Despite the health benefits of Vitis vinifera L. leaves, its anti-obesity potential has not been fully explored. In this work, we showed that Vitis vinifera L. leaf extract (VLE) inhibits the pancreatic lipase activity. Intragastric administration of VLE to mice led to a significant decrease in the body weight, tissue fat accumulation, levels of cholesterol, low-density lipoprotein and triglyceride compared to mice fed with high fat diet. We also found a lower level of neuropeptide-Y (NPY) in the serum and hypothalamus and a higher level of fibroblast growth factor 15 in mice supplemented with VLE. These results suggested that VLE regulates both the NPY-mediated pathway and the bile acid-FGF15 pathway to control energy metabolism and body weight gain. The composition of VLE was further investigated by a targeted metabolomics approach, which identified 21 compounds including phenolic acids, flavones, flavanols, flavanones, coumarins, and stilbenes. Taken together, we demonstrated the capacity of grape leaves in reducing obesity, which could be mediated by NPY and bile acids. Identification of putative active compounds in VLE also open the path for further studies to determine their effectiveness individually to treat obesity.

Nanoarchitectured hollow rod-like hierarchical carbon from Celosia cristata L. vascular bundles for supercapacitors

Xin-ya Zhao,Yu-fan Ma,Qiu-hong Bai,Xin-yi Feng,Yan Wang,Ye-hua Shen

Biomass has become an ideal choice for preparing high-performance carbon materials due to its unique morphological and composition advantages. The vascular bundle system of Celosia cristata L . and rich content of non-metallic elements provide an ideal template for preparing carbon materials with a unique hollow rod-like structure and enhanced electrochemical performance. Using Celosia cristata L . as a precursor, nitrogen and oxygen self-doped carbon materials were successfully prepared through activation process. The effects of activation temperature on the morphology, pore structure, specific surface area, and surface chemical properties of Celosia cristata L .-derived carbon materials were systematically studied. The carbon materials prepared at an appropriate activation temperature exhibited superior microstructure and electrochemical performance, displaying unique vascular bundle morphology and a rich porous structure with abundant oxygen and nitrogen elements. Based on this unique hierarchical pore structure and composition advantage of nitrogen-oxygen co-doping, in a three-electrode system, the specific capacitance of the carbon material was 337 F g −1 (0.5 A g −1 ), and the capacitance retention rate reached 110% after 50,000 cycles at a current density of 10 A g −1 , demonstrating excellent cycling stability. The assembled symmetric supercapacitor achieved a high energy density of 19.5 Wh kg −1 . Biomass materials with special intrinsic structures and compositions are of great significance in the development of high-performance energy storage materials and devices.