Preparation and properties of sulfated zirconia for hydrolysis of ethyl lactate

Weixing Li,Yingxiang Ni,Weiwei Liu,Weihong Xing,Nanping Xu 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.6

Sulfated zirconia catalysts are proposed for the reversible hydrolysis of ethyl lactate instead of liquid acids. Sulfated zirconia catalysts were prepared by precipitation-impregnation method. The zirconium hydroxide was produced from zirconium oxychloride by adding aqueous ammonia and then impregnated in sulfuric acid. The solid samples were obtained by filtration and evaporation of the mixtures, respectively. After the samples were calcined, the sulfated zirconia catalysts were prepared. The results showed that the catalyst prepared by evaporation has higher catalytic activity. The physicochemical characteristics of the sulfated zirconia catalysts were studied by thermal analysis, X-ray powder diffraction (XRD), temperature programmed desorption of ammonia (NH3-TPD) and N2 adsorption-desorption,respectively. By the precipitation-impregnation-evaporation method, the optimal sulfated zirconia catalyst of tetragonal phase was prepared under liquid-solid ratio of 5ml/g, 1 mol/L of H2SO4 and calcination at 650 oC for 3 h. The conversion of the ethyl lactate was 87.8% in 3 h at 85 oC with the catalyst loading 2 wt% and initial molar ratio of water to ethyl lactate 20 : 1.

A Microfluidic Hydrogel Chip with Orthogonal Dual Gradients of Matrix Stiffness and Oxygen for Cytotoxicity Test

Weixing Wang,Lili Li,Mingyu Ding,Guoan Luo,Qionglin Liang 한국바이오칩학회 2018 BioChip Journal Vol.12 No.2

The oxygen tensions and matrix stiffness play important roles in regulating cell response to cytotoxic drugs. In recent years, single spatiotemporal oxygen or matrix stiffness gradient has been established by various technologies for cell studies. However, the synergistic effects of the two factors on tumor cells remained elusive. In this study, we created a highly integrated and easy-to-operate microfluidic device. It was capable of generating more continuous, linear, stable and diffusive hydrogel stiffness gradient over a well-defined oxygen gradient. Sodium hydroxide and pyrogallol were used to scavenge oxygen and generate oxygen gradient, skillfully avoiding the utilization of bulky pressurized gas cylinders and sophisticated flow control by conventional methods. Utilizing the newly developed microfluidic device, we successfully performed drug test with a hypoxia sensitive anti-cancer drug, triapazamine (TPZ), on A549 cells under perpendicular construction of oxygen and spatially hydrogel stiffness gradients. The cell experiment results demonstrated the matrix stiffness-dependent cell drug resistance and hypoxia-induced cytotoxicity of TPZ. In summary, the developed microfluidic device exhibits high potential in the study of matrix stiffness-dependent cell responses and oxygen-sensitive drug cytotoxicity. Furthermore, the design principle can be functionally extended to other dual factors system and will facilitate the study of cell response in complex physiological and pathological conditions.

Pretreatment of sweet sorghum bagasse by alkaline hydrogen peroxide for enhancing ethanol production

Xudong Li,Weixing Cao,Chen Sun,Jiangping Qiu,Ronghou Liu,Le Zhang 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.3

Effects of severe and mild alkaline hydrogen peroxide (AHP) pretreatment on ethanol production from sweet sorghum bagasse via pre-simultaneous saccharification fermentation, and the chemical structure changes of the substrates were investigated. The results showed that the bagasse pretreated by severe AHP could produce more ethanol than that of mild AHP. The maximum ethanol concentration of the bagasses from mild and severe AHP pretreatment with 8% bagasse loading was 7.642±0.140 g/L and 19.330±0.085 g/L, respectively. Moreover, the FTIR and NMR analysis illustrated that the molecule and surface structures of the pretreated bagasse were significantly changed compared with the control. The potential biomass energy production of the effluent from the pretreatment was also briefly discussed for future utilization of waste solution.The heat energy potentials of waste solution with severe and mild AHP pretreatment were 367.2 kJ/Leffluent and 327.6 kJ/Leffluent, respectively.

Adaptive Multi-class Segmentation Model of Aggregate Image Based on Improved Sparrow Search Algorithm

Mengfei Wang,Weixing Wang,Sheng Feng,Limin Li 한국인터넷정보학회 2023 KSII Transactions on Internet and Information Syst Vol.17 No.2

Aggregates play the skeleton and supporting role in the construction field, high-precision measurement and high-efficiency analysis of aggregates are frequently employed to evaluate the project quality. Aiming at the unbalanced operation time and segmentation accuracy for multi-class segmentation algorithms of aggregate images, a Chaotic Sparrow Search Algorithm (CSSA) is put forward to optimize it. In this algorithm, the chaotic map is combined with the sinusoidal dynamic weight and the elite mutation strategies; and it is firstly proposed to promote the SSA’s optimization accuracy and stability without reducing the SSA’s speed. The CSSA is utilized to optimize the popular multi-class segmentation algorithm-Multiple Entropy Thresholding (MET). By taking three METs as objective functions, i.e., Kapur Entropy, Minimum-cross Entropy and Renyi Entropy, the CSSA is implemented to quickly and automatically calculate the extreme value of the function and get the corresponding correct thresholds. The image adaptive multi-class segmentation model is called CSSA-MET. In order to comprehensively evaluate it, a new parameter I based on the segmentation accuracy and processing speed is constructed. The results reveal that the CSSA outperforms the other seven methods of optimization performance, as well as the quality evaluation of aggregate images segmented by the CSSA-MET, and the speed and accuracy are balanced. In particular, the highest I value can be obtained when the CSSA is applied to optimize the Renyi Entropy, which indicates that this combination is more suitable for segmenting the aggregate images.

Low-Temperature Synthesis of Near-Monodisperse Globular MoS2 Nanoparticles with Sulphur Powders

Hui Wang,Xuequan Li,Kai Yan,유계성,Weixing Song,Ting Shen,Dechun Zou 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2017 NANO Vol.12 No.8

Nanoparticles (NPs) with high uniformity have been extensively investigated for their excellent chemical stability. Near-monodisperse globular MoS2 NPs were prepared with sulphur powders (SPs) as a sulphur source by a one-pot polyol-mediated process without surfactants, transfer agents and toxic agents at 170–190 ℃. The as-processed SPs greatly affected the formation of the MoS2 NPs after low-activity sulphur (S8)n was reassembled from common SPs (S8). The average size of MoS2 NPs can be reduced remarkably from 100–200 nm to 50 nm by introducing low amounts of MnCl2. A preliminary four-step growth mechanism based on the aggregation-coalescence model was also proposed. This green and simple method may be an alternative to the common hot-injection and heating-up methods for the preparation of monodisperse NPs, particularly transition metal dichalogenides.

Rheinic acid ameliorates radiation‑induced acute enteritis in rats through PPAR‑γ/NF‑κB

Haixia Sha,Yu Gu,Weixing Shen,Li Zhang,Fei Qian,Yudong Zhao,Haixiao Li,Ting Zhang,Weimin Lu 한국유전학회 2019 Genes & Genomics Vol.41 No.8

Background Acute radiation enteritis (ARE), a common complication of intestinal caused by abdominal and pelvic radiation therapy. Rheinic acid is a major active ingredient derived from Rhubarb. Rhubarb could suppress inflammation, tumor, fibrosis oxidative damage. However, RA as the main active component and extract monomer of Rhubarb, the pharmacological activity and the underlying molecular mechanism on various diseases has not yet been revealed. Objective To determine the potential role of rheinic acid (RA) in ameliorating inflammation of rats with acute radiation enteritis (ARE), and explore the underlying mechanism. Methods ARE rat model was established by irradiated with single-dose 10 Gy X-rays at a rate of 0.62 Gy/min to the abdomen. The rats were executed after orally administered with Rheinic acid 7 days and used in the subsequent experiments. Body weight, fecal characteristics and bloody of rats were used to assess the disease activity index. Histological analysis of the jejunum and colon were evaluated using H&E staining. The pro-inflammatory cytokines levels were measured by immunohistochemistry and ELISA. The levels of nitric oxide (NO), malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione (GSH) were also determined. The mRNA and protein expression were examined by real-time polymerase chain reaction (qRT-PCR) and western blot, respectively. Results Rheinic acid promoted intestinal functional recovery, and ameliorated intestinal damage and bloody stool in ARE rats. Rheinic acid strongly decreased the levels of tumor necrosis factor-α, interleukin-1, interleukin-6, NO, and MDA, whereas increased levels of anti-oxidants, SOD and GSH. Moreover, the expression of apoptosis-related proteins, cleaved caspase-3 and cleaved poly (ADP-ribose) polymerase (PARP), were decreased with RA treatment. Further study indicated that PPAR-γ was activated and thereby NF-κB and p38 MAPK signaling pathway were suppressed after rheinic acid treatment. Conclusion Rheinic acid could ameliorate acute radiation enteritis and the underlying molecular mechanism is, at least partially, through PPAR-γ/NF-κB and p38 MAPK/JNK pathways.

Current utilization of waste biomass as filler for wood adhesives: A review

Jinming Liu,Yongfeng Li,Hailin Mo,Enjun Xie,Jianlin Fang,Weixing Gan 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.115 No.-

Filler is one of the most important additives for wood adhesives. The introduction of filler offers variousfunctions for wood adhesives, such as the increase of initial viscosity, the decrease of permeability, theimprovement of bonding strength, and the reduction of production cost. However, flour, a grain resource,is widely used as a filler that is added to polymers in the production of wood-based panels. As a result, alarge number of edible resources are wasted every year. Waste biomass that biomass residues are abandonedin nature are a promising filler that can be used to replace flour. The utilization of waste biomass asfiller for wood adhesives to prepare wood-based panels not only improves its mechanical strength, butalso reduces formaldehyde emissions. However, most waste biomass shows disappointing prepressingproperties. Advances in the use of waste biomass as an alternative filler for wood adhesives werereviewed. In addition, the current limitations and future prospects of waste biomass were discussed. Recycling waste biomass is a useful way to avoid the enormous amount of waste generated by differentindustries and control environmental pollution. It contributes to the practical development of circulareconomy.

Preparation and characterization of chitosan-poly (vinyl alcohol)/polyvinylidene fluoride hollow fiber composite membranes for pervaporation dehydration of isopropanol

Jing Wang,Wenying Zhang,Weixing Li,Weihong Xing 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.7

A new hollow fiber composite membrane of chitosan-poly (vinyl alcohol)/polyvinylidene fluoride (CSPVA/ PVDF) was prepared by casting the solution of CS and PVA on PVDF hollow fiber support for pervaporation dehydration of isopropanol. The composite membranes were crosslinked with glutaraldehyde (GA) and sulfuric acid. The microstructure and physicochemical properties of the membranes were characterized by scanning electron microscope (SEM), attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), thermogravimetry (TG) and contact angle measurements. Results from SEM images showed that dense separation layers were successfully coated onto the supports, and the ATR-FTIR results showed that GA had crosslinked the composite membranes. Results of TG and contact angle showed the thermostability of membranes increased and the hydrophilicity decreased after blending CS and PVA. The swelling degree of composite membranes increased with increasing CS content and water content. Effects of the content of CS and GA in solution on membrane separation performance were investigated. The pervaporation experiments for dehydration of isopropanol showed that the membrane with 60 wt% CS and 0.1 wt% GA had a good separation performance. The permeate flux was 306 g/(m2·h) and the separation factor was 2140 for the feed solution containing 90% isopropanol at 60 oC. When the water content increased from 3 wt% to 15 wt%, the permeate flux increased from 207 g/(m2·h) to 346 g/(m2·h) while the separation factor decreased from 2406 to 1876. The separation factor and permeation flux increased with feed temperature.

Cerebrovascular Drug-Eluting Stent versus Bare-Metal Stent in the Treatment of Vertebral Artery Stenosis: A Non-Inferiority Randomized Clinical Trial

Yingkun He,Tianxiao Li,Weixing Bai,Liangfu Zhu,Meiyun Wang,You Zhang 대한뇌졸중학회 2019 Journal of stroke Vol.21 No.1

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Preparation and Self-Healing Behaviors of Poly(acrylic acid)/Cerium Ions Double Network Hydrogels

Hongwei Zhou,Guohe Xu,Jie Li,Shihao Zeng,Xiaolong Zhang,Zhaohui Zheng,Xiaobin Ding,Weixing Chen,Qiguan Wang,Wenzhi Zhang 한국고분자학회 2015 Macromolecular Research Vol.23 No.12

This work aims at developing an approach to poly(acrylic acid)/cerium ions (PAA/cerium ions) double network hydrogels and exploring the self-healing properties of the hydrogels, with expectation to provide some clues for constructing new healable gel actuators and enrich the family of self-healable hydrogels. The hydrogel is covalently crosslinked by a traditional crosslinking agent N,N'-methylene bis-acrylamide to form the first network and further physically crosslinked by the ionic interaction between cerium ions and the carboxyl groups in the hydrogel network. The preparation method and self-healing behaviors of the hydrogels are investigated.