POLYMER DEGRADATION AND STABILITY
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2020
·
IF 4.032
Yang Li,Yu Liu,Hongyu Zhu,Shirong Shuai,Cong Zhao,Kanghong Zhou,Wei Ge,Jianyuan Hao
Methoxy-poly (ethylene glycol)-block-poly (α-carboxyl-ε-caprolactone)/Fe 3 O 4 nanocomposites (mPEG-b-PCCL@Fe 3 O 4 ) with spherical shape, more negative and smoother surface and core-sell structure were prepared by simply changing the solvent. Their degradation behavior was systematically investigated at 37 °C in distilled water and buffers with different pH values. The mPEG-b-PCCL micelles were used as the contrast. Although the acid inhibition and basic promoting degradation were observed for both mPEG-b-PCCL@Fe 3 O 4 and micelles, the existence of magnetite nanoparticles (MNPs) and more surface –COOH slowed down the degradation of nanocomposites due to the dissociation hindrance of –COOH, the hydrophobicity and the cross-linking effects of MNPs. The degradation of mPEG-b-PCCL@Fe 3 O 4 underwent the surface degradation at initial time and bulk degradation after complete swelling of the hydrophobic core. These investigations suggested that the degradation of mPEG-b-PCCL@Fe 3 O 4 was more designable and controllable than that of micelles.
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高影响因子
CATALYSIS TODAY
·
2020
·
IF 5.825
Feng Jiang,Shanshan Wang,Jiao Zheng,Bing Liu,Yuebing Xu,Xiaohao Liu
Promoters, such as Na and Mn, play an important role in governing the active phase and catalytic performance of cobalt-based FTS catalyst. In this work, the dependence of the promotional effect of promoters on supports has been investigated by using the carbon and silica supported cobalt-based catalysts in the presence of Na, Mn, and both Na and Mn promoters, respectively. The characterization results of H 2 -TPR, CO-TPD and XRD profiles together with the FTS performances demonstrate the strong dependence of the promotional effect of promoter on the type of support used. The carbon support, which shows weak cobalt-support interaction, facilitates the manifestation of the effect of promoter. In detail, Mn can promote the formation of Co 2 C sites at the conditions of 260 °C, 0.5 MPa and lower H 2 /CO ratio, resulting from the promoted CO adsorption and subsequent dissociation. Thus, the suppressed adsorption of H 2 and the promoted surface dissociative C* concentration enhances the selectivities to lower olefins (C 2 = -C 4 = ) and C 5+ with a decrease in methane selectivity. Interestingly, the further addition of Na promoter shows synergistic effect of Na and Mn promoter on remarkably increasing selectivity to lower olefins due to the obviously suppressed chain growth. This synergistic effect could be observed only at the weak cobalt-carbon interaction with a more obvious effect at lower H 2 /CO ratio in feed gas that favors the increase of Co 2 C sites with mainly exposed facets of (111) and (020). The presence of (020) facet might be more crucial to enhance the formation of lower olefins. However, over silica support with strong cobalt-silica interaction, the promotional effect of Mn is obviously suppressed, which leads to only CoO and metallic Co sites in the FTS reaction and much weaker impact on product selectivity. The further addition of Na into Mn-promoted cobalt catalysts shows similar effect as Na promoter alone in the product selectivity where the chain growth is highly promoted to remarkably suppress methane selectivity and enhance selectivity to C 5+ rather than desired lower olefins. In contrast to carbon support, the strong cobalt-silica interaction leads to less promotional formation of CO 2 via the Boudouard reaction (2CO*→C* + CO 2 ) due to the increased non-dissociative adsorption of CO.
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ENERGY & FUELS
·
2020
·
IF 3.421
Suya Yin,Taishun Yang,Yuan Xue,Maiying Xie,Fengfei Chen,Hualin Lin,Bin Dai,Feng Gao,Sheng Han
High-efficiency pour point depressants (PPDs) for diesel fuel were obtained using a series of tetradecyl methacrylate-N-α-methacrylamide copolymers (C14MC-NMLR) with different molar ratios synthesized through radical polymerization of tetradecyl methacrylate (C14MC) and various forms of N-α-methacrylamide (NMLR, R = -phenyl, -naphthyl, -cyclohexyl, -14a, -16a, -18a). The copolymers were characterized by Fourier transform infrared spectroscopy, 1H nuclear magnetic resonance, and thermogravimetric analysis. Results showed that diesel treated with C14MC-NML-phenyl (9:1) and C14MC-NML-14a (6:1) presented better cold flow properties at 2000 ppm, and the reductions in cold filter-plug point (ΔCFPP) and solid point (ΔSP) were (23 and 10 °C) and (22 and 11 °C) at 2000 ppm, respectively. The depressive effects further improved after compounding. When they were combined at a 1:4 mass ratio, PPDC-6 presented the best depressive effects, and the ΔCFPP and ΔSP reached 25 and 11 °C at 1000 ppm dosage and 28 and 15 °C at 2000 ppm dosage, respectively. Additionally, the crystallization behavior and crystal morphology of each treated diesel were explored.
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高影响因子
JOURNAL OF FOOD BIOCHEMISTRY
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2020
·Vol. 44
·期 9
·e13361
·
IF 1.662
Yongsheng Chen,Sheng Geng,Benguo Liu
The demand for plant-derived antidiabetic nutraceuticals is increasing. In this study, the effects of three common caffeoylquinic acids (CQAs) (chlorogenic acid, isochlorogenic acid A, and cynarin) on α-glucosidase activity and glucose consumption in HepG2 cells were systematically compared. Their α-glucosidase inhibitory activities followed the order of isochlorogenic acid A > chlorogenic acid > cynarin. The fluorescence analysis indicated that they exerted the inhibitory role by forming the complex with α-glucosidase at the molar ratio of 1:1. Isochlorogenic acid A possessed the highest binding capacity, followed by chlorogenic acid and cynarin. The effect of caffeoyl group distribution on the α-glucosidase inhibitory activity was clarified by the molecular docking results. In the HepG2 cells, isochlorogenic acid A also showed the best glucose consumption with negligible cytotoxicity, which might be related to its reactive oxygen species scavenging capacity in cells. Our results confirm its potential application as the antidiabetic nutraceutical. Practical applications The hypoglycemic activities of three common CQAs (chlorogenic acid, isochlorogenic acid A, and cynarin) were systemically evaluated in this study. Isochlorogenic acid A exhibited the strongest α-glucosidase inhibitory activity and highest glucose consumption in HepG2 cells with low cytotoxicity. The results suggest that isochlorogenic acid A can be used as the potential hypoglycemic nutraceutical in functional foods.
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PubMed
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2020
·
IF 3.99
Fengyuan Zhang,Weiqu Liu,Liyan Liang,Chunhua Liu,Shuo Wang,Hongyi Shi,Yankun Xie,Maiping Yang,Ke Pi
Hydrophobic polydimethylsiloxane-functionalized graphene oxide (NH 2 -PDMS-GO), α, ω-bis(amino)-terminated polydimethylsiloxane (NH 2 -PDMS-NH 2 ) and graphene oxide (GO) are grafted into waterborne polyurethane (WPU) to enhance wettability , water resistance permeation and corrosion resistance properties. The result displays that the NH 2 -PDMS-GO and NH 2 -PDMS-NH 2 apparently improve the water contact angle of WPU. The value of water contact angle of WPU/NH 2 -PDMS-GO is 117°, and that of WPU/NH 2 -PDMS-NH 2 is 107.8°. They are higher than that of WPU (76.25°). The water absorption value of WPU is 8.34 wt.%. The values of WPU/NH 2 -PDMS-GO and WPU/NH 2 -PDMS-NH 2 are lower than that of WPU, which are 4.03 wt.% and 5.05 wt.%. For anti-corrosion performance, the WPU/NH 2 -PDMS-GO exhibits the best corrosion resistance ability, which displays the more positive corrosion potential (-0.08 V) and lower corrosion current density (3.636 × 10 −9 A cm -2 ) than others after 21 days immersion in 3.5 wt.% NaCl solution. The EIS results also show that the WPU/NH 2 -PDMS-GO reveals a well long-term corrosion resistance ability, and the impedance modulus Z 0.01Hz is still at 3.47 × 10 7 Ω cm 2 after 80 days immersion in 3.5 wt.% NaCl solution. The |Z| 0.01Hz of WPU decreases to 4.14 × 10 6 Ω cm 2 after 36 days. So, the NH 2 -PDMS-GO could effectively enhance the corrosion resistance of WPU.
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JOURNAL OF MOLECULAR LIQUIDS
·
2021
·
IF 6.165
Yuhuan Deng,Bin Liang,Xingtang Liang,Songlin Fan,Yanjuan Zhang,Yanzhen Yin,Huayu Hu,Zuqiang Huang,Yuben Qin
Chitin is difficult to be dissolved due to its dense structure, high crystallinity, and acetyl groups. Amorphization is conducive to enhancing the solubility of chitin. In this study, an effective mechanical activation-metal salt (MAMS) technology was used to pretreat α-chitin to improve its solubility in NaOH/urea solution. The chlorides of Fe and Al showed better synergistic effect with MA, especially FeCl 3 . The crystallization index of MA-FeCl 3 -pretreated chitin (MAFCCT) decreased to 4%, attributing to that Fe 3+ and Cl - jointly disrupted the intra- and intermolecular-hydrogen bonds in chitin. In addition, during the dissolution of MAFCCT, Fe 3+ fixed on chitin could form Fe(OH) 3 colloid with OH – to induce NaOH enter the interior of chitin molecules. The solubility of MAFCCT in NaOH/urea solution at −16 °C for 8 h reached 97.1%. MAMS pretreatment is a practical technology to enhance the solubility of chitin by destroying its stable crystal structure.
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ENERGY & FUELS
·
2021
·
IF 3.605
Fangwen Cheng,Shaoqi Zhan,Xinfeng Dai,Xiaofeng Huang,Binghui Wu,Nanfeng Zheng
α-FAPbI3-based perovskite solar cells have recently attracted increasing attention as a result of an ideal bandgap and longer exciton lifetime of FAPbI3 compared to perovskites with other compositions. However, in a traditional fabrication method, the α-FAPbI3 films were usually obtained by a direct phase transition from δ to α phase at a high annealing temperature, leading to low quality with poor crystallinity and numerous defects. The formation and stabilization of phase-pure, material-pure, high-quality α-FAPbI3 films remain challenging. In this work, a FA vapor-assisted cation-exchange pathway from low-dimensional perovskites to three-dimensional α-FAPbI3 was built, through which phase-pure and material-pure α-FAPbI3 films were achieved at 100 °C below the temperature of thermodynamic δ-to-α phase transition (∼150 °C). Through an in-depth study, the cation-exchange pathway was found to have a low reaction barrier directly toward α-FAPbI3 and suppress the formation of δ-FAPbI3, leading to high-quality α-FAPbI3 with high orientation and few trap states at a low annealing temperature. Consequently, small-area devices and large-area modules with as-prepared α-FAPbI3 films were achieved with improved performance, showing great potential for further study and application.
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高影响因子
APPLIED SURFACE SCIENCE
·
2021
·
IF 6.707
Enrou Mei,Xiaodong Liu,Ya Chen,Yanxia Yu,Zhaoping Chen,Keqin Yang,Xiaojuan Liang,Weidong Xiang
Recently, perovskite has received extensive attention due to their excellent photoelectric properties, while the instability of perovskite quantum dots (PQDs) has always troubled us. Herein, we proposed a simple coating mechanism to protect PQDs. Using oleic acid (OA) for etching α-Al 2 O 3 wafer to make the surface appear pore structure, and the PQDs was coated within the modified α-Al 2 O 3 wafer, thereby improving the stability of PQDs. The CsPbX 3 @α-Al 2 O 3 composite material can achieve the emission of blue-green–red (436 nm to 636 nm) through adjustable luminescence wavelength. The photoluminescence (PL) intensity of CsPbBr 3 @α-Al 2 O 3 composite material exposure to the air after 28 days can maintain over 50%. It is worth noticing that the photoluminescent quantum yield (PLQY) of CsPbBrI 2 @α-Al 2 O 3 composite material can reach 58%, the colour purity of CsPbBr 3 @α-Al 2 O 3 and CsPbBrI 2 @α-Al 2 O 3 achieve 97.1% and 99.8%, respectively. It was due to the high colour purity of the composite materials can the selected CIE colour coordinate monochromatic light encompassed 114% of NTSC colour gamut. Moreover, the warm white light-emitting diode (WLED) yielded bright natural white light and showed the luminous efficiency (LE) of 86.58 lm/W, colour rendering index (CRI) of 86.9, correlated colour temperature (CCT) of 4602 K. The LE and CRI reaches a relatively balanced value, which showed that this composite material has a certain development prospect in the WLED field.
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高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2019
·
IF 14.229
Sheng Guo,Haojie Wang,Wei Yang,Hussain Fida,Liming You,Kun Zhou
In this work, a cost-effective and eco-friendly calcium-doped α-Fe 2 O 3 (Ca-Fe 2 O 3 ) with abundant oxygen vacancies was fabricated using a scalable precipitation-calcination method to activate peroxymonosulfate (PMS) for wastewater purification. Density functional theory calculations revealed that the incorporation of Ca 2+ into the α-Fe 2 O 3 structure enhances the electron transfer from α-Fe 2 O 3 to PMS, facilitating the activation of PMS. The degradation of Rhodamine B by 5%Ca-Fe 2 O 3 proceeded with a reaction constant 8 times higher than that of pristine α-Fe 2 O 3 . This can be attributed to the increased generation of 1 O 2 and O 2 • − , increased specific surface area and enhanced electrical conductivity. The applicability of the 5%Ca-Fe 2 O 3 /PMS system was investigated including its operating parameters and stability, and the intermediates involved in the reaction were identified. The 5%Ca-Fe 2 O 3 /PMS system exhibited excellent degradation efficiency in natural water samples. This work opens up new perspectives for designing highly efficient catalysts and renders iron oxides potential candidates for environmental remediation.
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Biotechnology Journal
·
2019
·Vol. 14
·期 7
·1800643
·
IF 3.543
Liwei Gao,Shiying Li,Yanning Xu,Chengqiang Xia,Jiadi Xu,Jun Liu,Yuqi Qin,Xin Song,Guodong Liu,Yinbo Qu
α- l -Arabinofuranosidases are important in the degradation of plant polysaccharides and are used in several industrial processes. Although the use of filamentous fungi for the production of α- l -arabinofuranosidases is widely reported, there are few reports on strain engineering for enhanced production of these enzymes by fungi. In this study, the function of transcription factor AraR in l -arabinose release and catabolism by the fungus Penicillium oxalicum ( P. oxalicum ) is investigated. Also, a mutant of AraR, AraR A731V , is constructed to improve the production of α- l -arabinofuranosidases on the basis of the sequence homology between AraR and the xylanolytic gene activator XlnR. The AraR A731V -overexpressing strain can synthesize α- l -arabinofuranosidase in the absence of an inducer and shows a 54.1-fold increase in α- l -arabinofuranosidase production and a 7.4-fold increase in α-galactosidase production in the medium containing wheat bran. Determination of the transcript abundances of lignocellulolytic enzyme genes reveals significant upregulation of multiple α- l -arabinofuranosidase genes and downregulation of some cellulolytic and xylanolytic enzyme genes in the engineered strain relative to its parent. Taken together, the results suggest the conserved regulatory function of AraR in the family Trichocomaceae and provide a strategy for engineering fungal strains for enhanced α- l -arabinofuranosidase production. Graphical α- l -Arabinofuranosidases are important in plant cell-wall degradation and are used in many industries. In this study, it is shown that a point mutation of transcription factor AraR could increase α- l -arabinofuranosidase production by 54.1-fold in the fungus Penicillium oxalicum .
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PubMed
高影响因子
Biomed Research International
·
2019
·
IF 2.197
YiXun Li,Huan Li,Yong Duan,XueMei Cai,DingYun You,Feng Zhou,ChuanQi Yang,XiaoYu Tuo,ZiJie Liu
Background. Xuanwei City in Yunnan province has been one of the towns with highest lung cancer mortality in China. The high content of amorphous silica in the bituminous coal from Xuanwei of Yunnan is mainly present as irregular and spherical silica nanoparticles (SiNPs). It has been reported that silica nanoparticles in bituminous coal correlated with the high incidence of lung cancer in Xuanwei. To explore the role and mechanism of SiNPs in the tumorigenesis of lung cancer in Xuanwei, human mononuclear cells (THP-1) and human bronchial epithelial cells (BEAS-2B) were cocultured in a transwell chamber. Combined with Benzo[a]pyrene-7, 8-dihydrodiol-9, and 10-epoxide (BPDE), SiNPs could significantly promote the proliferation and Epithelial-Mesenchymal Transition (EMT) and inhibit apoptosis of BEAS-2B cells and induce the release of TGF-α from THP-1 cells. After neutralizing TGF-α with antibody, the proliferation and EMT were decreased and enhanced apoptosis of BEAS-2B cells. Furthermore, the results showed that TGF-α in the sera of patients with lung adenocarcinoma in Xuanwei were significantly higher than in patients with benign pulmonary lesions in Xuanwei and those with lung adenocarcinoma in outside of Xuanwei of Yunnan. Taken together, our study found that SiNPs promoted the proliferation and EMT of BEAS-2B cells by inducing the release of TGF-α from THP-1 cells.
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高影响因子
Journal of the American Chemical Society
·
2019
·
IF 14.695
Ji-Song Yao,Jing Ge,Kun-Hua Wang,Guozhen Zhang,Bai-Sheng Zhu,Chen Chen,Qun Zhang,Yi Luo,Shu-Hong Yu,Hong-Bin Yao
Cubic phase CsPbI3 quantum dots (α-CsPbI3 QDs) as a newly emerging type of semiconducting QDs hold tremendous promise for fundamental research and optoelectronic device applications. However, stable and sub-5 nm-sized α-CsPbI3 QDs have rarely been demonstrated so far due to their highly labile ionic structure and low phase stability. Here, we report a novel strontium-substitution along with iodide passivation strategy to stabilize the cubic phase of CsPbI3, achieving the facile synthesis of α-CsPbI3 QDs with a series of controllable sizes down to sub-5 nm. We demonstrate that the incorporation of strontium ions can significantly increase the formation energies of α-CsPbI3 QDs and hence reduce the structure distortion to stabilize the cubic phase at the few-nanometer size. The size ranging from 15 down to sub-5 nm of as-prepared stable α-CsPbI3 QDs allowed us to investigate their unique size-dependent optical properties. Strikingly, the few-nanometer-sized α-CsPbI3 QDs turned out to retain high photoluminescence and highly close packing in solid state thin films, and the fabricated red light emitting diodes exhibited high brightness (1250 cd m–2 at 9.2 V) and good operational stability (L50 > 2 h driven by 6 V). The developed cation-substitution strategy will provide an alternative method to prepare uniform and finely size-controlled colloidal lead halide perovskite QDs for various optoelectronic applications.
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高影响因子
危险品化学品经营许可证（带存储）