ACS Sustainable Chemistry & Engineering
·
2020
·
IF 7.632
Xinliang Li,Guancheng Jiang,Xiulun Shen,Gongrang Li
The hydration and swelling of shale formations are serious problems for well drilling. The use of an efficient shale inhibitor is one of the most important methods for overcoming the wellbore instability issue. In this work, poly-l-arginine (PArg) was synthesized and used as an efficient and biodegradable shale inhibitor. This inhibitor was systematically evaluated through measuring the swelling degree of the bentonite (Bent) pellet, the rheological behavior of the Bent suspensions, and the recovery percentage of shale cuttings. The results demonstrated that 2.0 wt % PArg could reduce the swelling degree of Bent to 70.53%, improve the shale recovery percentage to 71.40% at 180 °C, and inhibit 12.0 wt % Bent mud-making. The PArg displayed a highly inhibitive performance and excellent high-temperature resistance property, better than common inorganic KCl and organic polyether diamine. The underlying inhibition mechanism was also proposed based on measuring the variation of the interlayer spacing of the Bent, observing the exterior morphologies of Bent particles, and assessing the particle size distribution and electrokinetic potential. The results indicated that the PArg displayed its inhibitive effect mainly by adsorbing onto the Bent, encapsulating the Bent particles efficiently, and decreasing the interlayer spacing in a certain degree with 0.9 Å. This study can contribute to designing highly inhibitive water-based drilling fluids containing PArg.
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高影响因子
POLYMER
·
2019
·
IF 3.771
Yaxin Qiu,Qianru Wanyan,Wenyuan Xie,Zhifeng Wang,Ming Chen,Defeng Wu
An interesting biomass-derived shape memory polymer (SMP) based on cross-linked poly( l -malic acid) (PMA), with reconfigurable permanent shape and tunable shape memory transition temperature ( T trans ), was developed in this work. The amorphous cross-linked network was constructed in PMA using eco-friendly 1,8-octanediol as the cross-linker through a catalyst-free two-step way. The relations between crosslinking density ( d ) and glass transition temperature ( T g ), as well as the mechanical strengths of as-obtained cross-linked PMA (CPMA) were then evaluated. Both the strengths and the T trans are easily tunable by controlling curing times. Moreover, the permanent shape of CPMA is reconfigurable due to additional crosslinking in the heat treatment process. It also shows good diversity of processing approaches. This work is the first report to achieve good strengths on the biodegradable PMA and to activate its shape memory effect, opening up a window of application of PMA as the smart material or even as the common plastics.
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Journal of Functional Foods
·
2018
·
IF 3.47
Hong Ding,Xiaofei Li,Jian Li,Zhike Li,Yunhui Niu,Wanying Ren,Jianyang Tan,Shanye Yin
The present study examined the effects of procyanidin B2 (PB2) on L-NAME (nitric oxide synthase inhibitor)-induced hypertensive nephropathy. After 4 weeks of treatment with daily PB2 supplementation, lower blood pressure levels were observed in rats. The potential mechanisms were combined with amelioration of renal function impairment. The L-NAME–induced renal histological damage were reduced by PB2 treatment, which showed similar protective tendency in kidney injury molecule–1, nephrin, fibronectin and α–smooth muscle actin protein expression. This appears to be due to PB2 inducing a less pronounced generation of renal reactive oxygen species and inflammatory mediators than in the model group. Downregulation of Ang II type 1 receptor and NADPH oxidase subunit (NOX4, gp91phox and p47phox) played a critical role in the effect of PB2 reducing oxidative stress production. These activities could further support the use of PB2 commercially in food for the prevention of hypertension and its complications.
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高影响因子
Journal of Materials Chemistry B
·
2018
·Vol. 6
·期 26
·4314-4325
·
IF 4.776
Tao Liu,Shaohua Chen,Siyi Zhang,Xidong Wu,Peina Wu,Beiping Miao,Xiang Cai
Transferrin-functionalized chitosan-graft-poly(L-lysine) dendrons (CS–PLLD–Tf) were synthesized in this work and then used to deliver the MMP-9 shRNA plasmid to HNE-1 cells for gene therapy. The obtained CS–PLLD–Tf displayed excellent gene transfection in vitro, verifying the strategy of constructing a high-efficiency gene carrier by conjugating the multiple low generation PLLDs to one molecule of CS to form a copolymer. Particularly, CS–PLLD–Tf showed much higher gene transfection efficiency than PEI-25k and CS–PLLD in the presence of serum, and more than 40% HNE-1 cells were transfected. This result led to an obvious decrease in MMP-9 protein expression and the apoptosis of HNE-1 cells as well as inhibition of the growth and invasion of HNE-1 tumors. The in vivo anti-tumor assay showed that CS–PLLD–Tf delivered the MMP-9 plasmid effectively and the tumor volume decreased more than 77% compared with the PBS control group. Moreover, CS–PLLD–Tf displayed higher bioavailability and good biocompatibility such as lower cytotoxicity, excellent blood compatibility and non-toxicity to organs, suggesting a potential application in gene therapy of tumors.
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PubMed
高影响因子
BIOPROCESS AND BIOSYSTEMS ENGINEERING
·
2018
·Vol. 41
·期 9
·1347-1354
·
IF 2.139
Tang Xiao-Ling,Liu Xiao,Suo Hui,Wang Zhi-Chao,Zheng Ren-Chao,Zheng Yu-Guo
The tyrosine phenol lyase (TPL) catalyzed synthesis of L-DOPA was regarded as one of the most economic route for L-DOPA synthesis. In our previous study, a novel TPL from Fusobacterium nucleatum ( Fn -TPL) was exploited for efficient biosynthesis of L-DOPA. However, the catalytic efficiency decreased when the reaction system expanded from 100 mL to 1 L. As such, the bioprocess for scale-up production of L-DOPA was developed in this study. To increase the stability of substrate and product, as well as decrease the by-product formation, the optimum temperature and pH were determined to be 15 °C and pH 8.0, respectively. The initial concentration of pyrocatechol, pyruvate and ammonium acetate was fixed at 8, 5 and 77 g/L and a fed-batch approach was applied with sodium pyruvate, pyrocatechol and ammonium acetate fed in a concentration of 5, 5 and 3.5 g/L, respectively. In addition, L-DOPA crystals were exogenously added to inhibit cell encapsulation by the precipitated product. The final L-DOPA concentration reached higher than 120 g/L with pyrocatechol conversion more than 96% in a 15-L stirred tank, demonstrating the great potential of Fn -TPL for industrial production of L-DOPA.
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高影响因子
POLYMER INTERNATIONAL
·
2018
·Vol. 67
·期 9
·1221-1228
·
IF 2.352
Meng Ma,Kai Liu,Haiming Zheng,Si Chen,Bozhen Wu,Yanqin Shi,Xu Wang
Poly( l -lactic acid)/crosslinked polyurethane (PLLA/CPU) blends which were prepared via reactive blending of PLLA with poly( ϵ -caprolactone) (PCL), glycerol and 4,4′-methylenediphenyl diisocyanate showed excellent toughness. The effects of the composition of the mixture and degree of crosslinking of CPU on the toughness of the PLLA/CPU blends (80/20 w/w) were studied in detail. Dynamic mechanical analysis and rheological measurements were used to characterize the structure of the in situ formed CPU in the PLLA matrix. A novel netlike phase structure was observed when the average molecular weight of PCL and degree of crosslinking were 1 kDa and 10%, respectively. The impact strength of the blend was enhanced from 2.2 kJ m −2 for pure PLLA to 62.4 kJ m −2 ; meanwhile, the elongation at break was increased to 489.8%. Therefore, the mechanical properties of PLLA/CPU blends can be easily tailored by tuning the composition of the mixture and the degree of crosslinking of CPU. © 2018 Society of Chemical Industry
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高影响因子
Royal Society Open Science
·
2018
·Vol. 5
·期 11
·
IF 2.504
Chao Chen,Lei Cai,Xinchen Shangguan,Liang Li,Yanping Hong,Guoqiang Wu
Developing high-efficiency hetero-catalysts for transesterification reaction is of great importance in the production of biodiesel from Jatropha curcas L. seed oil (JO). Here, we synthesized a series of sulfated TiO2 by treating with varying H2SO4 concentration (SO42−/TiO2) and TiO2 catalysts and applied to the transesterification of JO. Furthermore, these heterostructures were characterized by many characterization methods including XRD, FT-IR, N2-adsorption, SEM, TEM, TG, py-IR and NH3-TPD, and their catalytic performance was investigated under various operating conditions. The results reveal that both the Brønsted and Lewis acid sites are presented in the SO42−/TiO2 catalysts, while only Lewis-type sites are observed in the TiO2 catalyst. And the acid intensity, surface area and mesoporous volume of catalysts are improved obviously after treating TiO2 with sulfuric acid. Then the SO42−/TiO2 catalysts exhibit much higher catalytic activity than TiO2 catalyst, which is attributed to the larger surface area and mesoporous volume and stronger acidity. Furthermore, the reusability behaviour of 1.5 SO42−/TiO2 catalyst in the transesterification of JO was also studied.
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高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2018
·
IF 3.779
Min Yang,Yujia Yan,Huanxian Shi,Cunjin Wang,Enzhou Liu,Xiaoyun Hu,Jun Fan
In the design of new fluorescence sensors, exploration of new sensors with excellent performances and smart designs for the detection of ions and biomolecules is of continuing interest. Therefore, we designed an inner filter effect (IFE) based sensor by effectively combining between CdTeS quantum dots (QDs) and Ag nanoparticles (NPs). Ternary alloyed CdTeS QDs were synthesized by two steps and using 3-mercaptopropionic acid (MPA) as stabilizer , polyvinylpyrrolidone (PVP) stabilized Ag NPs were prepared by crystal-seed. The emission peak of CdTeS QDs and the absorption peak of Ag NPs could availably overlap by changing the Te/S molar ratios and l -ascorbic acid (AA) concentrations. The CdTeS QDs/Ag NPs (QNs) with an obviously emission at 580 nm were used as IFE-based sensors for l -cysteine (L-Cys). The QNs fluorescence was increasing with addition of l -Cysteine (L-Cys), the fluorescence (PL) intensity (F/F 0 ) was linearly proportional to the L-Cys concentrations ranging from 20 μM to 400 μM with the correlation coefficient (R 2 ) of 0.9942 and the detection limit was calculated to be 0.025 μM (S/N = 3), where F and F 0 were the PL intensity in the presence and absence of L-Cys at 580 nm, respectively. Moreover, there was no interference to some potential interfering substances, which showed high sensitivity and selectivity for L-Cys.
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高影响因子
BIOMACROMOLECULES
·
2015
·
IF 5.75
Piming Ma,Long Jiang,Pengwu Xu,Weifu Dong,Mingqing Chen,Piet J. Lemstra
In this work we report the in situ preparation of fully biobased stereocomplex poly(lactide) (SC-PLA) nanocomposites grafted onto nanocrystalline cellulose (NCC). The stereocomplexation rate by compounding high-molar-mass poly(d-lactide) (PDLA) with comb-like NCC grafted poly(l-lactide) is rather high in comparison with mixtures of PDLA and PLLA. The rapid stereocomplexation was evidenced by a high stereocomplexation temperature (Tc-sc = 145 °C) and a high SC crystallinity (Xc-sc = 38%) upon fast cooling (50 °C/min) from the melt (250 °C for 2 min), which are higher than currently reported values. Moreover, the half-life crystallization time (175–190 °C) of the SC-PLA was shortened by 84–92% in comparison with the PDLA/PLLA blends. The high(er) stereocomplexation rate and the melt stability of the SC in the nanocomposites were ascribed to the nucleation effect of the chemically bonded NCC and the “memory effect” of molecular pairs in the stereocomplex melt because of the confined freedom of the grafted PLLA chains.
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高影响因子
Biomedical Materials
·
2015
·Vol. 10
·期 3
·035015
·
IF 3.697
Ding-Zhu Yang,Ai-Zheng Chen,Shi-Bin Wang,Yi Li,Xiao-Lin Tang,Yong-Jing Wu
Phase inversion using supercritical carbon dioxide (SC-CO2) has been widely used in the development of tissue engineering scaffolds, and particular attention has been given to obtaining desired morphology without additional post-treatments. However, the main challenge of this technique is the difficulty in generating a three-dimensional (3D) nanofiber structure with a rough surface in one step. Here, a poly(L-lactic acid) (PLLA) 3D nanofiber scaffold with a rough surface is obtained via phase inversion using SC-CO2 by carefully choosing fabrication conditions and porogens. It is found that this method can effectively modulate the structure morphology, promote the crystallization process of semicrystalline polymer, and induce the formation of rough structures on the surface of nanofibers. Meanwhile, the porogen of ammonium bicarbonate (AB) can produce a 3D structure with large pores, and porogen of menthol can improve the interconnectivity between the micropores of nanofibers. A significant increase in the fiber diameter is observed as the menthol content increases. Furthermore, the menthol may affect the mutual transition between the α' and α crystals of PLLA during the phase separation process. In addition, the results of protein adsorption, cell adhesion, and proliferation assays indicate that cells tend to have higher viability on the nanofiber scaffold. This process combines the characteristic properties of SC-CO2 and the solubility of menthol to tailor the morphology of polymeric scaffolds, which may have potential applications in tissue engineering.
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高影响因子
SCIENTIA HORTICULTURAE
·
2015
·
IF 1.365
Xiaofeng Ma,Yongping Wang,Mengxi Liu,Jianmin Xu,Zhigang Xu
The objectives of this study were to determine the effects of green light (G) and two red lights (R) of different wavelengths on the growth and the morphogenesis of potato plantlets in vitro . Randomized nodal explants were grown under five different light conditions: fluorescent white light (FL); the combined spectrum of blue light (B), G, and R at 630 nm (R 630 BG); the combined spectrum of B, G, and R at 660 nm (R 660 BG); the combined spectrum of B and R at 630 nm (R 630 B); and the combined spectrum of B and R at 660 nm (R 660 B). Morphogenesis, physiological parameters and leaf anatomical structure of potato plantlets in vitro were investigated. The results showed that R 630 BG and R 660 BG increased stem diameter and leaf area, and increased the amounts of chlorophyll, soluble sugar, soluble protein and starch in potato plantlets in vitro . Most of the stomata under R 660 BG were elliptical in shape. Leaves of potato plantlets in vitro grown under R 630 BG and R 660 BG had a distinct upper epidermis layer and palisade parenchyma layer. The addition of G to the combined spectrum of R and B contributed to the growth and development of potato plantlets in vitro more than the combined spectrum of R and B without G, and R at 660 nm was more effective in promoting plant growth than R at 630 nm.
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高影响因子
ACS Applied Materials & Interfaces
·
2015
·
IF 6.723
Mengzhen Dai,Lingen Sun,Long Chao,Yueming Tan,Yingchun Fu,Chao Chen,Qingji Xie
Electrochemical/chemical oxidative synthesis and biosensing/biofuel cell applications of poly(L-DOPA) (PD) are studied versus polydopamine (PDA) as a recent hotspot biomaterial. The enzyme electrode developed by coelectrodeposition of PD and glucose oxidase (GOx), uricase, or tyrosinase shows biosensing performance superior to that of the corresponding PDA-based enzyme electrode. The chemical oxidative polymerization of L-DOPA (PDC) by NaAuCl4 in GOx-containing neutral aqueous solution is used to immobilize GOx and gold nanoparticles (AuNPs). The thus-prepared chitosan (CS)/GOx-PDC-AuNPs/Auplate/Au electrode working in the first-generation biosensing mode responds linearly to glucose concentration with a sensitivity of 152 μA mM–1 cm–2, which is larger than those of the CS/GOx-PDAC-AuNPs/Auplate/Au electrode, the CS/GOx-poly(3-anilineboronic acid) (PABA)-AuNPs/Auplate/Au electrode, and the most reported GOx-based enzyme electrodes. This PDC-based enzyme electrode also works well in the second-generation biosensing mode and as an excellent bioanode in biofuel cell construction, probably because PD as an amino acid polymer has the higher biocompatibility and the more favorable affinity to the enzyme than PDA. The PD material of great convenience in synthesis, outstanding biocompatibility for preparing high-performance bionanocomposites, and strong capability of multifunctional coatings on many surfaces may find wide applications in diversified fields including biotechnology and surface-coating.
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高影响因子
危险品化学品经营许可证（带存储）