One-pot synthesis of lactic acid from cellulose over a sulfonated Sn-KIT6 catalyst

Weijie Cai,Qing Chen,Hao Xuan,Congming Li,Hao Yu,Li Cui,Zhihui Yu,Shaoyin Zhang,Fengzuo Qu 한국화학공학회 2019 Korean Journal of Chemical Engineering Vol.36 No.4

A sulfonated Sn-doped KIT-6 catalyst (Sn-KIT-6-Pr-SO3H) was successfully prepared via the hydrothermal self-assembly method, and its performance towards to value-added lactic acid production from one-pot conversion of renewable cellulose was investigated. Indeed, the physicochemical features of the as-prepared catalysts were deeply characterized by various techniques, including XRD, BET, SEM, FT-IR, XPS, UV-vis and TGA-DSC. The results confirmed its high BET surface area with an ultrahigh cross-linked framework and promising acid strength (co-existence of Brønsted and Lewis acidity). Additionally, the impact of different reaction factors, such as the type of catalysts, temperature, time, recyclability on cellulose conversion and the yield of targeted lactic acid, were determined. Meanwhile, the developed catalyst depicted the promising activity and stability under the optimal reaction conditions. It could be recycled at least four times without any obvious deactivation. This provides insight into developing efficient catalytic systems to convert renewable biomass into value-added chemicals.

Molecular cloning and expression analysis of the first two key genes through 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway from Pyropia haitanensis(Bangiales, Rhodophyta)

Yu Du,Jian Guan,Ruijun Xu,Xin Liu,Weijie Shen,Yafeng Ma,Yuan He,Songdong Shen 한국조류학회I 2017 ALGAE Vol.32 No.4

Pyropia haitanensis (T. J. Chang et B. F. Zheng) N. Kikuchi et M. Miyata is one of the most commercially usefulmacroalgae cultivated in southeastern China. In red algae, the biosynthesis of terpenoids through 2-C-methyl-Derythritol4-phosphate (MEP) pathway can produce a direct influence on the synthesis of many biologically importantmetabolites. In this study, two genes of cDNAs, 1-deoxy-D-xylulose-5-phosphate synthase (DXS) and 1-deoxy-Dxylulose-5-phosphatereductase (DXR), which encoding the first two rate-limiting enzymes among MEP pathway werecloned from P. haitanensis. The cDNAs of P. haitanensis DXS (PhDXS) and DXR (PhDXR) both contained complete openreading frames encoding polypeptides of 764 and 426 amino acids residues, separately. The expression analysis showedthat PhDXS was significant differently expressed between leafy thallus and conchocelis as PhDXR been non-significant. Additionally, expression of PhDXR and its downstream gene geranylgeranyl diphosphate synthase were both inhibitedby fosmidomycin significantly. Meanwhile, we constructed types of phylogenetic trees through different algae and higherplants DXS and DXR encoding amino acid sequences, as a result we found tree clustering consequences basically in linewith the "Cavalier-Smith endosymbiotic theory." Whereupon, we speculated that in red algae, there existed only completeMEP pathway to meet needs of terpenoids synthesis for themselves; Terpenoids synthesis of red algae derivativesthrough mevalonate pathway came from two or more times endosymbiosis of heterotrophic eukaryotic parasitifer. Thisstudy demonstrated that PhDXS and PhDXR could play significant roles in terpenoids biosynthesis at molecular levels. Meanwhile, as nuclear genes among MEP pathway, PhDXS and PhDXR could provide a new way of thinking to researchthe problem of chromalveolata biological evolution.

Thermal Penetration of Aircraft Tyre Tread at Touchdown

Yu Li,Weiji Wang 한국항공우주학회 2024 International Journal of Aeronautical and Space Sc Vol.25 No.3

Most studies of friction and heat conduction in aircraft tyres at touchdown are limited to the tread surface. However, it is necessary to know the thermal penetration inside the tread to study the quantity of the potential decomposed and lost material by the frictional heat. Additionally, a high tread surface temperature does not necessarily guarantee a stronger thermal penetration inside the tread because of several factors. Therefore, it is necessary to establish a relationship between the tyre tread surface temperature and the internal heat penetration under the aircraft touchdown scenario. A model is established on MATLAB to simulate the aircraft tyre dynamics and tread heat conduction at touchdown. This model is capable of calculating the temperature increase in the tread, both on the surface and inside. It can also be used to determine the depth of thermal decomposition caused by frictional heat. Additionally, the study found that the Thermal Decomposition Depth to Surface Temperature Ratios (DTRs) are similar across the tread (the depth of thermal decomposition at each part of the tread surface is proportional to the surface temperature). Therefore, it can estimate the thermal penetration throughout the tread by simply calculating the surface temperature of the entire tread and the average DTR at several points of interest. The study provides a more straightforward approach for aircraft tyre thermal wear prediction and future research.

Hydrothermal Synthesis of Nanosized Sulfated Zirconia as an Efficient and Reusable Catalyst for Esterification of Acetic Acid with n-Butanol

Yu, Shengjian,Jiang, Pingping,Dong, Yuming,Zhang, Pingbo,Zhang, Yue,Zhang, Weijie Korean Chemical Society 2012 Bulletin of the Korean Chemical Society Vol.33 No.2

A kind of nanosized sulfated zirconia was prepared by a hydrothermal method, and full characterized by XRD, TEM, BET, TGA, and FTIR. Its catalytic activity was evaluated in the esterification reactions, including the testing of the catalytic reusability and the optimization of reaction conditions. The obtained catalyst was revealed to be highly efficient solid catalyst for the esterification of acetic acid with n-butanol, presenting the advantages of high conversion and selectivity, easy recovery, and steady reusability.

Effects of Soil Amendment on Tomato and Physical Properties in Soil

Hongjun Yu,Weijie Jiang,Zitian Xiao,Ming Wang 한국원예학회 2008 한국원예학회 기타간행물 Vol.- No.-

Molecular cloning and expression analysis of the first two key genes through 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway from Pyropia haitanensis (Bangiales, Rhodophyta)

Du, Yu,Guan, Jian,Xu, Ruijun,Liu, Xin,Shen, Weijie,Ma, Yafeng,He, Yuan,Shen, Songdong The Korean Society of Phycology 2017 ALGAE Vol.32 No.4

Pyropia haitanensis (T. J. Chang et B. F. Zheng) N. Kikuchi et M. Miyata is one of the most commercially useful macroalgae cultivated in southeastern China. In red algae, the biosynthesis of terpenoids through 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway can produce a direct influence on the synthesis of many biologically important metabolites. In this study, two genes of cDNAs, 1-deoxy-D-xylulose-5-phosphate synthase (DXS) and 1-deoxy-D-xylulose-5-phosphate reductase (DXR), which encoding the first two rate-limiting enzymes among MEP pathway were cloned from P. haitanensis. The cDNAs of P. haitanensis DXS (PhDXS) and DXR (PhDXR) both contained complete open reading frames encoding polypeptides of 764 and 426 amino acids residues, separately. The expression analysis showed that PhDXS was significant differently expressed between leafy thallus and conchocelis as PhDXR been non-significant. Additionally, expression of PhDXR and its downstream gene geranylgeranyl diphosphate synthase were both inhibited by fosmidomycin significantly. Meanwhile, we constructed types of phylogenetic trees through different algae and higher plants DXS and DXR encoding amino acid sequences, as a result we found tree clustering consequences basically in line with the "Cavalier-Smith endosymbiotic theory." Whereupon, we speculated that in red algae, there existed only complete MEP pathway to meet needs of terpenoids synthesis for themselves; Terpenoids synthesis of red algae derivatives through mevalonate pathway came from two or more times endosymbiosis of heterotrophic eukaryotic parasitifer. This study demonstrated that PhDXS and PhDXR could play significant roles in terpenoids biosynthesis at molecular levels. Meanwhile, as nuclear genes among MEP pathway, PhDXS and PhDXR could provide a new way of thinking to research the problem of chromalveolata biological evolution.

Hydrothermal Synthesis of Nanosized Sulfated Zirconia as an Efficient and Reusable Catalyst for Esterification of Acetic Acid with n-Butanol

Shengjian Yu,Pingping Jiang,Yuming Dong,Pingbo Zhang,Yue Zhang,Weijie Zhang 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.2

A kind of nanosized sulfated zirconia was prepared by a hydrothermal method, and full characterized by XRD,TEM, BET, TGA, and FTIR. Its catalytic activity was evaluated in the esterification reactions, including the testing of the catalytic reusability and the optimization of reaction conditions. The obtained catalyst was revealed to be highly efficient solid catalyst for the esterification of acetic acid with n-butanol, presenting the advantages of high conversion and selectivity, easy recovery, and steady reusability.

Boost-type push-pull converter with reduced switches

Gu, Aiyu,Sun, Weijie,Zhang, Guidong,Chen, Sizhe,Wang, Yu,Yang, Ling,Zhang, Yun The Korean Institute of Power Electronics 2020 JOURNAL OF POWER ELECTRONICS Vol.20 No.3

This paper develops and analyses a boost-type push-pull converter with a reduced number of switches. The newly designed converter mainly consists of five diodes, two switches, two inductors, a transformer and two capacitors. By tuning the duty cycle and the transformer ratio, different voltage gains of the proposed converter can be obtained. It is notable for its electrical isolation characteristics. When compared with traditional step-up converters, the step-up module and converter module share the same switch. In addition, the control of the converter becomes easier to implement, and it has better stability and a reduced volume. It should be mentioned that the number of switches in the proposed converter is decreased but maintains the same voltage stress when compared to the traditional structure. The operating principle of proposed converter is demonstrated, which is followed by the design of the component parameters. To validate the feasibility of the proposed topology, an experimental prototype is constructed to verify its correctness and practicability of the proposed converter when compared with the conventional converter.

Comparative Study of Two Common In Vitro Models for the Pancreatic Islet with MIN6

Chao Xinxin,Zhao Furong,Hu Jiawei,Yu Yanrong,Xie Renjian,Zhong Jianing,Huang Miao,Zeng Tai,Yang Hui,Luo Dan,Peng Weijie 한국조직공학과 재생의학회 2023 조직공학과 재생의학 Vol.20 No.1

BACKGROUND: Islet transplantation is currently considered the most promising method for treating insulin-dependent diabetes. The two most-studied artificial islets are alginate-encapsulated b cells or b cell spheroids. As three-dimensional (3D) models, both artificial islets have better insulin secretory functions and transplantation efficiencies than cells in twodimensional (2D) monolayer culture. However, the effects of these two methods have not been compared yet. Therefore, in this study, cells from the mouse islet b cell line Min6 were constructed as scaffold-free spheroids or alginate-encapsulated dispersed cells. METHODS: MIN6 cell spheroids were prepared by using Agarose-base microwell arrays. The insulin secretion level was determined by mouse insulin ELISA kit, and the gene and protein expression status of the MIN6 were performed by Quantitative polymerase chain reaction and immunoblot, respectively. RESULTS: Both 3D cultures effectively promoted the proliferation and glucose-stimulated insulin release (GSIS) of MIN6 cells compared to 2D adherent cells. Furthermore, 1% alginate-encapsulated MIN6 cells demonstrated more significant effects than the spheroids. In general, three pancreatic genes were expressed at higher levels in response to the 3D culture than to the 2D culture, and pancreatic/duodenal homeobox-1 (PDX1) expression was higher in the cells encapsulated in 1% alginate than that in the spheroids. A western blot analysis showed that 1% alginate-encapsulated MIN6 cells activated the phosphoinositide 3-kinase (PI3K)/serine/threonine protein kinase (AKT)/forkhead transcription factor FKHR (FoxO1) pathway more than the spheroids, 0.5% alginate-, or 2% alginate-encapsulated cells did. The 3D MIN6 culture, therefore, showed improved effects compared to the 2D culture, and the 1% alginate-encapsulated MIN6 cells exhibited better effects than the spheroids. The upregulation of PDX1 expression through the activation of the PI3K/AKT/FoxO1 pathway may mediate the improved cell proliferation and GSIS in 1% alginate-encapsulated MIN6 cells. CONCLUSION: This study may contribute to the construction of in vitro culture systems for pancreatic islets to meet clinical requirements.

Physical, Chemical Properties and Structural Changes of Zaodan Pickled by Vacuum Decompression Technology

Naxin Sun,Huiping Liu,Xiaowei Zhang,Hongni Wang,Shaojuan Liu,Pei Chen,Weijie Yu,Kai Liu 한국축산식품학회 2018 한국축산식품학회지 Vol.38 No.2

To shorten the production cycle of Zaodan, this study first pickled Zaodan by a novel technology -vacuum decompression technology. Vacuum decompression technology could reduce the pickling time of Zaodan from 20wkto about 9wk.The protein content, moisture and pH of the Zaodan egg white gradually decreased with a concomitant increase in salt during the pickling process. The total sulfhydryl group (SH) group content of the egg white proteins was increased to 2.43×10-3mol/L after being pickled for 30 d, whereas the content of disulphide bonds (SS) was reduced to 23.35×10-3mol/L. The surface hydrophobicity was lowest after pickling for 30 d. In addition, great changes occurred in the secondary structure of the egg white proteins after pickling for 20 d. The disappearance of ovomucin was noticeable based on sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis.