MACROMOLECULES
·
2021
·
IF 5.985
Lidong Feng,Xinchao Bian,Gao Li,Xuesi Chen
In order to obtain the forming regulation and structural evolution of poly(l-lactide)/poly(d-lactide) (PLLA/PDLA) stereocomplexes (sc-PLA), a commercial high molecular weight PLLA was blended with a series of PDLAs with different weight-average molecular weights (Mw) in the range of 7.5–290 kg·mol–1 by solution blending. The thermal properties, morphology, and thermal stability of the PLLA/PDLA blends were investigated by differential scanning calorimetry (DSC), field emission scanning electron microscopy (FE-SEM), and thermogravimetric analysis (TGA). The crystallization of sc-PLA and homochiral PLA (homo-PLA) was competitive and controlled by the Mw of PDLA. The phase structure of the PLLA/PDLA blends depended on the melting temperature. By quenching sc-PLA from 280 to 290 °C, a bicontinuous phase structure was observed for PLLA and PDLA. When quenching sc-PLA from 230 to 270 °C, a stereoamorphous mesophase of PLA (sam-PLA) was obtained, which originated from the residual strong hydrogen bonding between PLLA and PDLA. sam-PLA was a new discovery different from sc-PLA and homo-PLA. The PLLA/PDLA blends are not fully compatible among sam-PLA, PLLA, and PDLA. During melting, sc-PLA changed into sam-PLA, and the hydrogen bonding in sam-PLA was destroyed and weakened with increasing temperature at <∼270 °C. At higher than ∼270 °C, the hydrogen bonding became extremely weak and even disappeared.
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高影响因子
ACS Omega
·
2021
·
IF 3.512
Mingzhu Yao,Chen Liang,Shuangquan Yao,Yang Liu,Hui Zhao,Chenni Qin
The adsorption of hemicellulose derived from bagasse onto nanofibril cellulose has been studied in terms of kinetics and thermodynamics. In situ monitoring of bagasse hemicellulose with different molecular weights onto the nanofibril cellulose surfaces has been investigated using quartz crystal microbalance and dissipation. Then, the adsorption kinetics and thermodynamic properties were analyzed. Also, the sorption behavior and the adsorption layer properties were quantified in aqueous solutions. The maximum adsorption mass was 2.8314 mg/m2 at a concentration of 200 mg/L. Also, compared with that of the low-molecular-weight hemicellulose, the adsorption capacity of the high-molecular-weight hemicellulose was higher, and the adsorption rate changed faster and could reach an equilibrium in a shorter time. The intraparticle diffusion kinetic model represented the experimental data very well. Therefore, the kinetics of hemicellulose on the fiber adsorption was commonly described by a three-stage process: mass to transfer, diffusion, and equilibrium. The Gibbs energy change of the adsorption of hemicellulose was found to range from −20.04 to −49.75 kJ/mol at 25 °C. The entropy change was >0. It was found that the adsorption was spontaneous, and the adsorbed mass increased with the increase in temperature. This strengthened the conclusion that the adsorption process of the bagasse hemicellulose on the NFC was driven by the increase in entropy caused by the release of water molecules due to hydrophobic interaction or solvent reorganization.
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PubMed
高影响因子
ChemSusChem
·
2021
·Vol. 14
·期 23
·5311-5319
·
IF 8.928
Jianwang Xu,Xinge Miao,Lei Liu,Yantao Wang,Weiran Yang
Graphical Transfer hydrogenation : 5-Methylfurfural (5-MF), a promising C 6 platform molecule, is directly produced from biomass-derived carbohydrates by iodide-mediated transfer hydrogenation. Under the optimized conditions, 30–50 % of 5-MF is yielded from low-cost sugars and starch with 5-MF productivity as high as 103 mmol g cat −1 h −1 . The catalytic system is simple, robust, recyclable, and preferable to other approaches for the production of 5-MF. Herein, a robust catalytic system was developed for the green synthesis of 5-methylfurfural (5-MF) by iodide-mediated transfer hydrogenation. Around 50 % of 5-MF was yielded from d -fructose within 7.5 min using NaI as the catalyst and formic acid as both the hydrogen source and co-catalyst. The catalytic system was used for six consecutive cycles without any decrease in the yield. Various starch and raw biomass could be used as promising starting materials for 5-MF synthesis with moderate yields, and the productivity of 5-MF from corn starch reached 103 mmol g cat −1 h −1 , which is comparable with the best result from l -rhamnose. Moreover, the co-production of 5-MF and furfural from raw biomass makes this methodology more competitive than other routes.
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PubMed
高影响因子
GREEN CHEMISTRY
·
2021
·Vol. 23
·期 12
·4560-4566
·
IF 10.182
Yunhao Gao,Zhiyuan Zhou,Xi Chen,Yuyang Tian,Yan Li,Huachen Wang,Xuan Li,Xueyang Yu,Yongsong Cao
Volatilization and leaching are two critical pathways for pesticide transportation from their applied areas to non-target regions. Nanocarrier-based formulations can improve the use efficiency and reduce the off-target effects of pesticides, however, the complicated preparation process seriously restricts the large-scale application of nanopesticides in the agricultural field. In this work, taking 2-(2,4-dichlorophenoxy) acetic acid (2,4-D), 2-methyl-4-chlorophenoxyacetic acid (MCPA), and 3,5-dibromo-4-hydroxybenzonitrile (bromoxynil) as model herbicides, herbicide-intercalated Zn–Al hydrotalcites (herbicide@HTlcs) were facilely fabricated by a modified co-precipitation method without heating, aging, organic solvents, and inert gas. The obtained herbicide@HTlcs showed high entrapment efficiencies (71.7%–86.7%), a sheet structure with an average size of 339.4 nm, and positive surface charges (+40.5). The volatilities of herbicide@HTlcs were reduced more than 3-fold compared with those of pure herbicides. The release rates of 2,4-D@HTlcs were in line with the selectivity sequence of HTlcs for the anions and controlled by non-Fickian diffusion. The leaching experiments performed in two agricultural topsoils collected from Beijing and Yunnan province and a grassland soil from Neimenggu province all demonstrated that the developed 2,4-D@HTlc nanosheets could evidently retard 2,4-D leaching through the soil. Additionally, 2,4-D@HTlcs exhibited no delay in the control efficacy against Amaranthus retroflexus compared with free 2,4-D sodium salt. This study provides a novel insight into the facile fabrication of controlled release formulations of pesticides that can reduce the volatilization and leaching risks simultaneously.
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JOURNAL OF FOOD BIOCHEMISTRY
·
2021
·Vol. 45
·期 7
·e13771
·
IF 2.72
Chao Xin,Mengya Zhao,Jiahui Wang,Zhenyu Wang
Hawthorn berry has been proved hypoglycemic effect due to the presence of some α-glucosidase inhibitors. Herein, screening and identifying of α-glucosidase inhibitors from hawthorn berry were conducted, and the results showed polyphenols mainly containing quercetin (74.58%) and hyperioside (9.58%) were responsible for its bioactivity. In order to enhance the hypoglycemic effect, the combined glucose-lowering complex (DEH) consisting of hawthorn polyphenols, D-chiro-inositol (DCI), and epigallocatechin gallate (EGCG) was prepared, where three ingredients exerted the synergistic hypoglycemic effect to enhance glucose consumption and glycogen levels and inhibit hepatic gluconeogenesis in IR-HepG2 cells. In STZ/HFD-induced mice, DEH effectively improved insulin resistance, reduced fasting blood glucose (FBG) and hepatic gluconeogenesis, and increased hepatic glycogen synthesis and storage via down-regulation of PI3K/Akt/FOXO1-mediated PEPCK and G6Pase and up-regulation of PI3K/Akt/GSK3-mediated GS activation in the liver. In summary, these findings indicate that DEH is a potential novel strategy for the treatment of type 2 diabetes. Practical applications Glucose-lowering complex (DEH) with superior hypoglycemic effect, can effectively improve the insulin resistance, reduce the fasting blood glucose, hepatic gluconeogenesis and increase the hepatic glycogen synthesis and storage in mice, which represents a potential novel strategy for the treatment of type 2 diabetes.
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PubMed
高影响因子
TRANSPORT IN POROUS MEDIA
·
2021
·Vol. 144
·期 1
·133-148
·
IF 3.019
Dai Caili,Chu Zhongzhong,Jiang Qihui,Wu Yining,He Long,Zhao Mingwei
Polymer solution has extremely extensive applications in many natural and industrial processes, especially in oilfield development field, such as polymer flooding, fracturing and water shut-off. Thus, the study of flow behaviors of polymer in formation pores is significantly important. In this paper, the flow behaviors of the polymer droplets in the 3-D pore throat structure were systematically studied. Additionally, the influencing factors (polymer concentration, molecular weight and pore throat ratio, for instance) were investigated. As the increasing of polymer concentration and molecular weight, the polymer droplets were more difficult to break, which means the critical flow rate decreased and the average sizes of the first daughter droplets (FDD) were longer synchronously. Moreover, with the increase in pore throat ratio, the critical flow rate increased and the length of the FDD decreased. In addition, the prediction models of the length of the FDD with polymer concentration and pore throat ratio were established, respectively. The prediction model revealed that the length of the FDD satisfied an exponential relationship with the polymer concentration and a linear relationship with the pore throat ratio. Finally, the average size of droplets after macroscopic core flooding experiment was 8 μm and 17 μm when the polymer concentration was 0.01% and 0.1%, respectively. The results were consistent with the breakup behaviors of polymer droplets in the microscopic pore throat structure.
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Catalysts
·
2020
·Vol. 10
·期 9
·1057
·
IF 3.52
Jing Wang,Sheng Xu,Yang Pang,Xin Wang,Kequan Chen,Pingkai Ouyang
To achieve efficient bio-production of phospholipase D (PLD), PLDs from different organisms were expressed inE.coli. An efficient secretory expression system was thereby developed for PLD. First, PLDs fromStreptomycesPMF andStreptomyces racemochromogeneswere separately over-expressed inE.colito compare their transphosphatidylation activity based on the synthesis of phosphatidylserine (PS), and PLDPMFwas determined to have higher activity. To further improve PLDPMFsynthesis, a secretory expression system suitable for PLDPMFwas constructed and optimized with different signal peptides. The highest secretory efficiency was observed when the PLD * (PLDPMFwith the native signal peptide Nat removed) was expressed fused with the fusion signal peptide PelB-Nat inE. coli. The fermentation conditions were also investigated to increase the production of recombinant PLD and 10.5 U/mL PLD was ultimately obtained under the optimized conditions. For the application of recombinant PLD to PS synthesis, the PLD properties were characterized and 30.2 g/L of PS was produced after 24 h of bioconversion when 50 g/L phosphatidylcholine (PC) was added.Keywords:phospholipase D;phosphatidylserine;secretory expression;enzymatic catalysis
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Neural Regeneration Research
·
2020
·
IF 3.171
Jian-Zhu Bo,Ling Xue,Shuang Li,Jing-Wen Yin,Zheng-Yao Li,Xi Wang,Jun-Feng Wang,Yan-Shu Zhang
Although exogenous D-serine has been applied as a neural regulatory intervention in many studies, the role played by D-serine in hippocampal injuries caused by lead exposure remains poorly understood. Rat models of chronic lead exposure were established through the administration of 0.05% lead acetate for 8 weeks. Simultaneously, rats were administered 30 or 60 mg/kg D-serine, intraperitoneally, twice a day. Our results showed that D-serine treatment shortened the escape latency from the Morris water maze, increased the number of times that mice crossed the original platform location, and alleviated the pathological damage experienced by hippocampal neurons in response to lead exposure. Although D-serine administration did not increase the expression levels of the N-methyl-D-aspartate receptor subtype 2B (NR2B) in the hippocampi of lead-exposed rats, 60 mg/kg D-serine treatment restored the expression levels of NR2A, which are reduced by lead exposure. These findings suggested that D-serine can alleviate learning and memory impairments induced by lead exposure and that the underlying mechanism is associated with the increased expression of NR2A in the hippocampus. This study was approved by the Animal Ethics Committee of North China University of Science and Technology, China (approval No. LX2018155) on December 21, 2018.
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高影响因子
LANGMUIR
·
2020
·
IF 3.557
Mei Cui,Yuhao Duan,Yuanyuan Ma,Khaled W.A. Al-Shwafy,Yudong Liu,Xudong Zhao,Renliang Huang,Wei Qi,Zhimin He,Rongxin Su
Expansin has nonhydrolytic disruptive activity and synergistically acts with cellulases to enhance the hydrolysis of cellulose. The adsorption–desorption of expansin on noncellulosic lignin can greatly affect the action of expansin on lignocellulose. In this study, three lignins with different sources (kraft lignin (KL), sodium lignin sulfonate (SLS), and enzymatic hydrolysis lignin (EHL)) were selected as the substrates. The real-time adsorption–desorption of Bacillus subtilis expansin (BsEXLX1) on lignins was monitored using quartz crystal microgravimetry with dissipation (QCM-D). The effects of temperature and Tween 80 on the adsorption–desorption behaviors were also investigated. The results show that BsEXLX1 exhibited high binding ability on lignin and achieved maximum adsorption of 283.2, 273.8, and 266.9 ng cm–2 at 25 °C on KL, SLS, and EHL, respectively. The maximum adsorption decreased to 148.2–192.8 ng cm–2 when the temperature increased from 25 to 45 °C. Moreover, Tween 80 competitively bound to lignin and significantly prevented expansin adsorption. After irreversible adsorption of Tween 80, the maximum adsorption of BsEXLX1 greatly decreased to 33.3, 37.2, and 10.3 ng cm–2 at 25 °C on KL, SLS, and EHL, respectively. Finally, a kinetic model was developed to analyze the adsorption–desorption process of BsEXLX1. BsEXLX1 has a higher adsorption rate constant (kA) and a lower desorption rate constant (kD) on KL than on SLS and EHL. The findings of this study provide useful insights into the adsorption–desorption of expansin on lignin.
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高影响因子
ANALYTICAL CHEMISTRY
·
2020
·
IF 6.785
Juan Qiao,Han Wu,Huan Wei,Lanqun Mao,Tie Wang,Li Qi
To monitor d-glucose (Glu) in complex aqueous media with a high specificity, a conceptually new “selective capture and controllable detection” nanoreactor was explored. We designed and synthesized poly maleic anhydride-styrene-N-isopropylacrylamide-(4-aminophenyl) boronic acid [P(MAn-St-NIPAm-PBA)] to fabricate the nanoreactor. On the surface of the self-assembled, micelle-based nanoreactor, the stereo precise placement PBA provided a recognition unit in the block copolymer structure to boost the selective capture of Glu over other saccharides. P(MAn-St-NIPAm) served as the thermal sensitive moiety of the nanoreactor, which embedded with glucose oxidase and myoglobin-based catalyst in order to realize the controllable enzymolysis of Glu through temperature alteration. Once the nanoreactor was mixed with Glu, an obvious change in the UV–visible intensity of quinine produced in the multienzymolysis was observed. Glu in the rat microdialysates of brain ischemia was successfully monitored by the nanoreactor method, demonstrating the feasibility of constructing high-specificity nanoreactors for cerebral system applications.
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高影响因子
JOURNAL OF POLYMER RESEARCH
·
2020
·Vol. 27
·期 8
·1-10
·
IF 2.426
Han Shuo,Peng Yanyan,Tao Shengyun,Hu Ying,Lan Tianqi,Hu Chengkang,Cao Jing
In this work, a kind of chiral helical polymer PDTDH of 9,9-dipropynylfluorene skeleton structure were prepared. The structure and chiral properties of the obtained polymer were characterized by Nuclear Magnetic Resonance (NMR) and Circular Dichroism (CD) Spectroscopy. These chiral PDTDH polymers were used to fabricate chiral sensors and to investigate the enantioselective recognition of D−/L- tartaric acid enatiomer. The results indicated that the (S)-PDTDH/GCE sensor showed obvious response toward the tested tartaric acid enantiomer, which was confirmed by two parameters: Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) tests. These findings expand the scope for the application of chiral polymer as electrode modification material in the electrochemical chiral recognition field.
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高影响因子
Green Energy & Environment
·
2020
·
IF 6.395
Pengfei Liu,Christian Marcus Pedersen,Jiaojiao Zhang,Rui Liu,Zhenzhou Zhang,Xianglin Hou,Yingxiong Wang
Ternary deep eutectic solvents (TDESs) comprising choline chloride (ChCl), glycerol and l -arginine were synthesized as catalysts and solvents for the conversion of d -glucosamine (GlcNH 2 ) into deoxyfructosazine (DOF). The interactions between these three components in the prepared TDESs were studied by 1 H-, 35 Cl-NMR spectra and 1 H diffusion-ordered spectroscopy (DOSY) measurements. The chemical shift changes of active hydrogen in the 1 H-NMR spectra of TDES system and widening of signals in the 35 Cl-NMR spectra confirmed the hydrogen bonding interaction between the components, which was further supported by the decrease of diffusion coefficients ( D ) of the TDES components according to 1 H DOSY measurements. The influences of reaction temperature and l -arginine content in the TDESs on the yield of DOF were also studied. The experimental results have shown that when the molar ratio of ChCl, glycerol, and l -arginine was 1:2:0.1, DOF was the major product with a yield of 22.6% at 90 °C for 120 min. The chemical shift titration indicated that the carboxyl group of l -arginine in the TDES is the catalytical active site, so the mechanism of the catalytic reaction between GlcNH 2 and the TDES was proposed. Moreover, a reaction intermediate, dihydrofructosazine, was identified in the self-condensation reaction of GlcNH 2 by an in situ 1 H NMR technique.
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