Cationic surface modification of cellulose nanocrystals: Toward tailoring dispersion and interface in carboxymethyl cellulose films

Li, Mei-Chun,Mei, Changtong,Xu, Xinwu,Lee, Sunyoung,Wu, Qinglin Elsevier 2016 Polymer Vol.107 No.-

<P><B>Abstract</B></P> <P>The present work describes the development of high performance cellulose nanocrystals/carboxymethyl cellulose (CNC/CMC) films through a rational design of CNC surface chemistry. Considering the anionic surface nature of CMC, surface cationization of CNCs was performed in order to build strong interfacial bonding by electrostatic attraction and form uniform dispersion state by electrostatic repulsion. Nanocomposite films were fabricated by dispersing the CNCs and cationically modified CNCs (mCNCs) in CMC matrix through solution casting. The resultant CNC/CMC and mCNC/CMC films were then evaluated in terms of processability, mechanical properties and fracture surface morphology. Results showed that the reinforcing capacity of mCNCs was greatly dependent on its substitution degree. High substitution degree was favorable for obtaining mCNC/CMC film with uniform dispersion and superior mechanical properties. The observed distinctive reinforcing phenomena from CNCs and mCNCs in CMC matrix were interpreted in terms of dispersion state and interfacial bonding based on the fracture surface morphology.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Cationic cellulose nanocrystals (CNCs) are synthesized through etherification. </LI> <LI> Substitution degree (DS) is tuned by controlling water content in reaction system. </LI> <LI> Cationic CNCs are firstly used to reinforce carboxymethyl cellulose (CMC) films. </LI> <LI> The DS of cationic CNCs plays critical role on their dispersion in CMC films. </LI> <LI> Superior reinforcement of CMC films is achieved using cationic CNCs with higher DS. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Simultaneous optimization of multiparameters on a subcritical organic Rankine cycle system for low-grade waste heat recovery

Li Zhang,Chun-Chun Li,You-Rong Li,Chun-Mei Wu 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.1

This study aims to improve the thermo-economic performance of the subcritical organic Rankine cycle (ORC). Accordingly, an economical evaluation and the simultaneous multiparametric optimization on the subcritical ORC system for recovering low-grade waste heat of flue gas were conducted using electricity production cost (EPC) as the evaluation indicator. Results show that the optimum evaporating and condensing temperatures are mainly influenced by the inlet temperatures of flue gas and cooling fluid, respectively. High critical temperature of working fluids indicates high thermal-economic performance of the ORC system for 19 kinds of selected working fluids. Furthermore, the optimum pinch point temperature difference of evaporator decreases and that of condenser increases with the variation in the critical temperature of working fluids, but the optimum condensing temperature is unchanged. On the basis of a large number of calculation data, the correlations among the optimum cycle and external operating parameters of the subcritical ORC are proposed. These correlations can guide the engineering design of the subcritical ORC system.

Soy Protein Isolate As Fluid Loss Additive in Bentonite–Water-Based Drilling Fluids

Li, Mei-Chun,Wu, Qinglin,Song, Kunlin,Lee, Sunyoung,Jin, Chunde,Ren, Suxia,Lei, Tingzhou American Chemical Society 2015 ACS APPLIED MATERIALS & INTERFACES Vol.7 No.44

<P>Wellbore instability and formation collapse caused by lost circulation are vital issues during well excavation in the oil industry. This study reports the novel utilization of soy protein isolate (SPI) as fluid loss additive in bentonite–water based drilling fluids (BT-WDFs) and describes how its particle size and concentration influence on the filtration property of SPI/BT-WDFs. It was found that high pressure homogenization (HPH)-treated SPI had superior filtration property over that of native SPI due to the improved ability for the plugging pore throat. HPH treatment also caused a significant change in the surface characteristic of SPI, leading to a considerable surface interaction with BT in aqueous solution. The concentration of SPI had a significant impact on the dispersion state of SPI/BT mixtures in aquesous solution. At low SPI concentrations, strong aggregations were created, resulting in the formation of thick, loose, high-porosity and high-permeability filter cakes and high fluid loss. At high SPI concentrations, intercatlated/exfoliated structures were generated, resulting in the formation of thin, compact, low-porosity and low-permeability filter cakes and low fluid loss. The SPI/BT-WDFs exhibited superior filtration property than pure BT-WDFs at the same solid concentraion, demonstrating the potential utilization of SPI as an effective, renewable, and biodegradable fluid loss reducer in well excavation applications.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2015/aamick.2015.7.issue-44/acsami.5b07883/production/images/medium/am-2015-07883j_0012.gif'></P>

Intermedins A and B; New Metabolites from Schisandra propinqua var. intermedia

Li, Hong-Mei,Lei, Chun,Luo, Yong-Ming,Li, Xiao-Nian,Li, Xiao-Lei,Pu, Jian-Xin,Zhou, San-Yun,Li, Rong-Tao,Sun, Han-Dong 대한약학회 2008 Archives of Pharmacal Research Vol.31 No.6

A new dibenzocyclooctadiene lignan, intermedin A (1), and a new natural bisabolane sesquiterpenoid, intermedin B (2), were isolated from the aerial parts of Schisandra propinqua var. intermedia. Their structures were elucidated on the basis of extensive spectroscopical analysis.

Mechanical Performance, Water Absorption Behavior and Biodegradability of Poly(methyl methacrylate)-Modified Starch/SBR Biocomposites

Mei-Chun Li,Xin Ge,조을룡 한국고분자학회 2013 Macromolecular Research Vol.21 No.7

Natural corn starch was modified by surface grafting with poly(methyl methacrylate) (PMMA) through emulsion copolymerization and then compounded with styrene-butadiene rubber (SBR) latex in order to prepare PMMA-modified starch/SBR biocomposites. The effect of methyl methacrylate (MMA) and starch concentration on the mechanical properties, morphology, toluene swelling behavior, water absorption behavior and biodegradability of PMMA-modified starch/SBR biocomposites was investigated. Results showed that the optimum mechanical properties were achieved when the concentrations of MMA and starch were 10 and 30 phr, respectively, which could be also confirmed through the observations from FE-SEM micrographs and equilibrium welling test. Guth-Gold and Halpin-Tsai models were employed to predict the modulus of PMMA-modified starch/SBR biocomposites. Halpin-Tsai model was better fitted with the experimentally measured data than Guth-Gold model. The water absorption ratio of PMMA-modified starch/SBR biocomposites was strongly influenced by the immersion time and the starch concentration, which further caused a significant effect on the biodegradability of biocomposites.

Cellulose Nanocrystals and Polyanionic Cellulose as Additives in Bentonite Water-Based Drilling Fluids: Rheological Modeling and Filtration Mechanisms

Li, Mei-Chun,Wu, Qinglin,Song, Kunlin,De Hoop, Corneils F.,Lee, Sunyoung,Qing, Yan,Wu, Yiqiang American Chemical Society 2016 INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH - Vol.55 No.1

<P>This research aims to develop low cost, sustainable, environmentally friendly, and high performance water-based drilling fluids (WDFs) using bentonite (BT), polyanionic cellulose (PAC), and cellulose nanocrystals (CNCs). The effect of concentration of BT, PAC, and CNCs on the rheological and filtration properties of PAC/CNC/BT-WDFs was investigated. Eight empirical rheological models were applied to fit quantitatively the fluid properties. Results showed that the presence of PAC, CNCs, and BT improved the rheological and filtration properties of the WDFs. Among the eight empirical rheological models, the Sisko model performed the best in simulating the rheological behavior of the fluids. At the same concentration level of PAC and CNCs, CNCs had more impact on the rheological properties, whereas PAC had more influence on the filtration property. The incorporation of PAC resulted in very low permeable filter cakes, leading to the excellent filtration property. The combined use of PAC and CNCs yielded better rheological and filtration properties.</P>

Ginsenoside Rg1 Induces Apoptosis through Inhibition of the EpoR-Mediated JAK2/STAT5 Signalling Pathway in the TF-1/Epo Human Leukemia Cell Line

Li, Jing,Wei, Qiang,Zuo, Guo-Wei,Xia, Jing,You, Zhi-Mei,Li, Chun-Li,Chen, Di-Long Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.6

Ginsenoside Rg1 is one effective anticancer and antioxidant constituent of total saponins of Panax ginseng (TSPG), which has been shown to have various pharmacological effects. Our previous study demonstrated that Rg1 had anti-tumor activity in K562 leukemia cells. The aim of this study was designed to investigate whether Rg1 could induce apoptosis in TF-1/Epo cells and further to explore the underlying molecular mechanisms. Here we found that Rg1 could inhibit TF-1/Epo cell proliferation and induce cell apoptosis in vitro in a concentration and time dependent manner. It also suppressed the expression of EpoR on the surface membrane and inhibited JAK2/STAT5 pathway activity. Rg1 induced up-regulation of Bax, cleaved caspase-3 and C-PAPR protein and down-regulation of Bcl-2 and AG490, a JAK2 specific inhibitor, could enhance the effects of Rg1. Our studies showed that EpoR-mediated JAK2/STAT5 signaling played a key role in Rg1-induced apoptosis in TF-1/Epo cells. These results may provide new insights of Rg1 protective roles in the prevention a nd treatment of leukemia.

Emulsion Grafting Vinyl Monomers onto Starch for Reinforcement of Styrene-Butadiene Rubber

Mei-Chun Li,Xin Ge,조을룡 한국고분자학회 2013 Macromolecular Research Vol.21 No.5

Three types of modified starches (MST): Starch-g-poly(butyl acrylate) (ST-g-PBA), starch-g-poly (methyl methacrylate) (ST-g-PMMA) and starch-g-polystyrene (ST-g-PS) latexes were successfully synthesized by emulsion polymerization. These synthesized MST latexes were then directly compounded with styrene-butadiene rubber (SBR) latex in order to prepare MST/SBR compounds. The vulcanization characteristics, morphology, swelling ratio, mechanical and dynamic mechanical properties were investigated. Results indicated that the incorporation of starch or MST led to both an increase in the torque values and the cure rate of SBR compounds. MST with a particle size of approximately 200-400 nm uniformly dispersed in the SBR matrix, indicating the significantly improved dispersion. MST/SBR compounds exhibited better mechanical properties compared with starch/SBR (ST/SBR)compounds. Among the MST/SBR compounds, ST-g-PMMA/SBR compounds showed optimum tensile strength,which was even higher than that of carbon black/SBR (CB/SBR) compounds with the same loading of fillers. Finally, the reinforcing mechanism of MST in the SBR matrix was discussed.

Randomized Control Study of Nedaplatin or Cisplatin Concomitant with Other Chemotherapy in the Treatment of Advanced Non-small Cell Lung Cancer

Li, Chun-Hong,Liu, Mei-Yan,Liu, Wei,Li, Dan-Dan,Cai, Li Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.2

Objective: To observe the short-term efficacy, long-term survival time and adverse responses with nedaplatin (NDP) or cisplatin (DDP) concomitant with other chemotherapy in treating non-small cell lung cancer. Materials and Methods: A retrospective, randomized, control study was conducted, in which 619 NSCLC patients in phases III and IV who were initially treated and re-treated were randomly divided into an NDP group (n=294) and a DDP group (n=325), the latter being regarded as controls. Chemotherapeutic protocols (CP/DP/GP/NP/TP) containing NDP or DDP were given to both groups. Patients in both groups were further divided to evaluate the clinical efficacies according to initial and re-treatment stage, pathological pattern, type of combined chemotherapeutic protocols, tumor stage and surgery. Results: The overall response rate (ORR) and disease control rate (DCR) in the NDP group were 48.6% and 95.2%, significantly higher than in the DDP group at 35.1% and 89.2%, respectively (P<0.01). In NSCLC patients with initial treatment, squamous carcinoma and phase III, there were significant differences in ORR and DCR between the groups (P<0.05), while ORR was significant in patients with adenocarcinoma, GP/TP and in phase IIIa (P<0.05). There was also a significant difference in DCR in patients in phase IIIb (P<0.05). According to the statistical analysis of survival time of all patients and of those in clinical phase III, the NDP group survived significantly longer than the DDP group (P<0.01). The rates of decreased hemoglobin and increased creatinine, nausea and vomiting in the NDP group were evidently lower than in DDP group (P<0.05). Conclusion: NDP concomitant with other chemotherapy is effective for treating NSCLC, with higher clinical efficacy than DDP concomitant with chemotherapy, with advantages in prolonging survival time and reducing toxic and adverse responses.

Intermedins A and B; New Metabolites from Schisandra propinqua var. intermedia

Hong-Mei Li,Chun Lei,Yong-Ming Luo,Xiao-Nian Li,Xiao-Lei Li,Jian-Xin Pu,San-Yun Zhou,Rong-Tao Li,Han-Dong Sun 대한약학회 2008 Archives of Pharmacal Research Vol.31 No.6

A new dibenzocyclooctadiene lignan, intermedin A (1), and a new natural bisabolane sesquiterpenoid, intermedin B (2), were isolated from the aerial parts of Schisandra propinqua var. intermedia. Their structures were elucidated on the basis of extensive spectroscopical analysis.