Genipin-Crosslinked, Immunogen-Reduced Decellularized Porcine Liver Scaffold for Bioengineered Hepatic Tissue

Xiujuan Wu,Yujia Wang,Qiong Wu,Yi Li,Li Li,Jing Tang,Yujun Shi,Hong Bu,Ji Bao,Mingjun Xie 한국조직공학과 재생의학회 2015 조직공학과 재생의학 Vol.12 No.6

Liver disease affects millions of patients each year worldwide. Decellularized biologic matrices are plausible biomedical materials for bioengineered replacement hepatic tissue. However, one of the concerns for its safe medical application is the lack of objective assessment of the immunogen within the materials and in vivo immune responses to the matrices. The purpose of this study was to produce immunogen- reduced and biocompatible matrices from porcine liver. Whole porcine livers were perfusion decellularized and cross-linked with glutaraldehyde (GA) or genipin (GP). Proteins were extracted, and the migratory response of human leukocytes toward protein extracts was examined using an in vitro migration chamber. In addition, biopsy specimens of decellularized scaffolds were implanted subcutaneously into rodents to investigate scaffold immunogenicity. Histological staining confirmed cellular clearance from pig livers, with removal of nuclei and cytoskeletal components and widespread preservation of structural extracellular molecules. Polymerase chain reaction analysis showed that galactose-alpha-1,3-galactose-beta-1,4-N-acetylglucosamine (1,3 gal), swine leukocyte antigen, and porcine endogenous retrovirus were completely removed in the matrices. Decellularization significantly reduced the migration of monocytes compared with native porcine tissue. Although the proportion of transmigrating lymphocytes was much lower, repeating the cross-linking procedure reduced the migratory response. After implantation for 4 weeks, the decellularized and native samples were degraded, and the GA-treated group demonstrated a severe inflammatory reaction; however, minimal inflammatory cell infiltration was seen in the GPtreated group during the 8-week investigation period. In conclusion, our study provided evidence that GP crosslinking could significantly reduce the immunogenicity of decellularized liver biomaterials.

User Identification Using Real Environmental Human Computer Interaction Behavior

( Tong Wu ),( Kangfeng Zheng ),( Chunhua Wu ),( Xiujuan Wang ) 한국인터넷정보학회 2019 KSII Transactions on Internet and Information Syst Vol.13 No.6

In this paper, a new user identification method is presented using real environmental human-computer-interaction (HCI) behavior data to improve method usability. User behavior data in this paper are collected continuously without setting experimental scenes such as text length, action number, etc. To illustrate the characteristics of real environmental HCI data, probability density distribution and performance of keyboard and mouse data are analyzed through the random sampling method and Support Vector Machine(SVM) algorithm. Based on the analysis of HCI behavior data in a real environment, the Multiple Kernel Learning (MKL) method is first used for user HCI behavior identification due to the heterogeneity of keyboard and mouse data. All possible kernel methods are compared to determine the MKL algorithm’s parameters to ensure the robustness of the algorithm. Data analysis results show that keyboard data have a narrower range of probability density distribution than mouse data. Keyboard data have better performance with a 1-min time window, while that of mouse data is achieved with a 10-min time window. Finally, experiments using the MKL algorithm with three global polynomial kernels and ten local Gaussian kernels achieve a user identification accuracy of 83.03% in a real environmental HCI dataset, which demonstrates that the proposed method achieves an encouraging performance.

Detecting Malicious Social Robots with Generative Adversarial Networks

( Bin Wu ),( Le Liu ),( Zhengge Dai ),( Xiujuan Wang ),( Kangfeng Zheng ) 한국인터넷정보학회 2019 KSII Transactions on Internet and Information Syst Vol.13 No.11

Malicious social robots, which are disseminators of malicious information on social networks, seriously affect information security and network environments. The detection of malicious social robots is a hot topic and a significant concern for researchers. A method based on classification has been widely used for social robot detection. However, this method of classification is limited by an unbalanced data set in which legitimate, negative samples outnumber malicious robots (positive samples), which leads to unsatisfactory detection results. This paper proposes the use of generative adversarial networks (GANs) to extend the unbalanced data sets before training classifiers to improve the detection of social robots. Five popular oversampling algorithms were compared in the experiments, and the effects of imbalance degree and the expansion ratio of the original data on oversampling were studied. The experimental results showed that the proposed method achieved better detection performance compared with other algorithms in terms of the F1 measure. The GAN method also performed well when the imbalance degree was smaller than 15%.

Fabrication of High-Aspect-Ratio Microwire Electrodes Using a Vertical Liquid Membrane Electrochemical Etching Method

Yumeng Sang,Xiujuan Wu,Yongbin Zeng,Tao Yang 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.21 No.7

A vertical liquid membrane electrochemical etching method is proposed for the fabrication of high-aspect-ratio microwire electrodes. The potential and current density distributions are simulated using COMSOL software. The simulation results show that the unique potential distribution generated by the proposed method, combined with reciprocating linear motion of the wire electrode, can be used to fabricate microwire electrodes with large aspect ratio. These simulation results are verified experimentally. Different concentrations of electrolyte result in different reaction rates and thus different distributions of the diffusion layer and different bubble flows, resulting in different morphologies of the prepared wire electrodes. The effect of electrolyte concentrations is studied experimentally. At low electrolyte concentrations, the products of electrolysis are removed from the processing area under the action of gravity, and uniform electrodes with high aspect ratio can be prepared. At high electrolyte concentrations, intense bubble production destroys the diffusion layer around the electrode and leads to a dynamic equilibrium state, allowing the preparation of uniform wire electrodes in a rough machining process. The proposed method can prepare wire electrodes with different initial diameters. In this paper, uniform wire electrodes of length 1900 μm, diameter 7 μm, and aspect ratio 270 are fabricated by the proposed method from a tungsten wire of initial diameter 50 μm.

Sulfur-free exfoliated graphite with large exfoliated volume: Preparation, characterization and its adsorption performance

Qi Zhao,Xiujuan Yu,Xiuwen Cheng,Juan Wu 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.6

Sulfur-free exfoliated graphite (EG) with large exfoliated volume (760 mL g-1) was prepared throughchemical oxidation, followed by microwave exfoliation. SEM results indicated that well-developednetwork pores in the worm-like structure of EG could be clearly observed. XPS results displayed thatsome functional groups were yielded on the surface of the as-prepared EG. Moreover, the capacity of EGwas evaluated by the adsorption of rodamine B and 4-chlorophenol aqueous solution. Results showedthat EG exhibited high adsorption capacity for RhB and 4-CP, which could be attributed to the functionalgroups and well-developed network pores in the worm-like EG.

Water as an Oxygen Source: Synthesis, Characterization, and Reactivity Studies of a Mononuclear Nonheme Manganese(IV) Oxo Complex

Sawant, Sarvesh C.,Wu, Xiujuan,Cho, Jaeheung,Cho, Kyung‐,Bin,Kim, Sun Hee,Seo, Mi Sook,Lee, Yong‐,Min,Kubo, Minoru,Ogura, Takashi,Shaik, Sason,Nam, Wonwoo WILEY‐VCH Verlag 2010 Angewandte Chemie Vol.122 No.44

<P><B>Kontrollierte Herkunft</B>: Experimente mit isotopenmarkiertem Wasser lassen keinen Zweifel an der Quelle von Sauerstoff in einem Nicht‐Häm‐Mangan(IV)‐Oxo‐Komplex. Der mit Wasser als Sauerstoffquelle und einem Cer(IV)‐Oxidationsmittel gebildete Komplex (siehe Bild) aktiviert C‐H‐Bindungen von Alkylarenen und oxidiert aromatische Substrate (Sub) sowie Benzylalkohol.</P>

Enhanced Electron-Transfer Reactivity of Nonheme Manganese(IV)–Oxo Complexes by Binding Scandium Ions

Yoon, Heejung,Lee, Yong-Min,Wu, Xiujuan,Cho, Kyung-Bin,Sarangi, Ritimukta,Nam, Wonwoo,Fukuzumi, Shunichi American Chemical Society 2013 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.135 No.24

<P>One and two scandium ions (Sc<SUP>3+</SUP>) are bound strongly to nonheme manganese(IV)–oxo complexes, [(N4Py)Mn<SUP>IV</SUP>(O)]<SUP>2+</SUP> (N4Py = <I>N</I>,<I>N</I>-bis(2-pyridylmethyl)-<I>N</I>-bis(2-pyridyl)methylamine) and [(Bn-TPEN)Mn<SUP>IV</SUP>(O)]<SUP>2+</SUP> (Bn-TPEN = <I>N</I>-benzyl-<I>N</I>,<I>N</I>′,<I>N</I>′-tris(2-pyridylmethyl)-1,2-diaminoethane), to form Mn<SUP>IV</SUP>(O)–(Sc<SUP>3+</SUP>)<SUB>1</SUB> and Mn<SUP>IV</SUP>(O)–(Sc<SUP>3+</SUP>)<SUB>2</SUB> complexes, respectively. The binding of Sc<SUP>3+</SUP> ions to the Mn<SUP>IV</SUP>(O) complexes was examined by spectroscopic methods as well as by DFT calculations. The one-electron reduction potentials of the Mn<SUP>IV</SUP>(O) complexes were markedly shifted to a positive direction by binding of Sc<SUP>3+</SUP> ions. Accordingly, rates of the electron transfer reactions of the Mn<SUP>IV</SUP>(O) complexes were enhanced as much as 10<SUP>7</SUP>–fold by binding of two Sc<SUP>3+</SUP> ions. The driving force dependence of electron transfer from various electron donors to the Mn<SUP>IV</SUP>(O) and Mn<SUP>IV</SUP>(O)–(Sc<SUP>3+</SUP>)<SUB>2</SUB> complexes was examined and analyzed in light of the Marcus theory of electron transfer to determine the reorganization energies of electron transfer. The smaller reorganization energies and much more positive reduction potentials of the Mn<SUP>IV</SUP>(O)–(Sc<SUP>3+</SUP>)<SUB>2</SUB> complexes resulted in remarkable enhancement of the electron-transfer reactivity of the Mn<SUP>IV</SUP>(O) complexes. Such a dramatic enhancement of the electron-transfer reactivity of the Mn<SUP>IV</SUP>(O) complexes by binding of Sc<SUP>3+</SUP> ions resulted in the change of mechanism in the sulfoxidation of thioanisoles by Mn<SUP>IV</SUP>(O) complexes from a direct oxygen atom transfer pathway without metal ion binding to an electron-transfer pathway with binding of Sc<SUP>3+</SUP> ions.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2013/jacsat.2013.135.issue-24/ja403965h/production/images/medium/ja-2013-03965h_0014.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja403965h'>ACS Electronic Supporting Info</A></P>

Elucidating Bottlenecks to the Efficient Preparation of AB₅-Hexamer Mucosal Adjuvant Protein LTm by Genetic Engineering

( Di Liu ),( Fabiao Hu ),( Wenpeng Wang ),( Dong Wu ),( Xiujuan He ),( Wenyun Zheng ),( Haipeng Liu ),( Xingyuan Ma ) 한국미생물생명공학회(구 한국산업미생물학회) 2017 Journal of microbiology and biotechnology Vol.27 No.8

Escherichia coli heat-labile enterotoxin (LT) and its non-toxic mutant (LTm) are well-known powerful mucosal adjuvants and immunogens. However, the yields of these adjuvants from genetically engineered strains remain at extremely low levels, thereby hindering their extensive application in fundamental and clinical research. Therefore, efficient production of these adjuvant proteins from genetically engineered microbes is a huge challenge in the field of molecular biology. In order to explore the expression bottlenecks of LTm in E. coli, we constructed a series of recombinant plasmids based on various considerations and gene expression strategies. After comparing the protein expression among strains containing different recombinant plasmids, the signal sequence was found to be critical for the expression of LTm and its subunits. When the signal sequence was present, the strong hydrophobicity and instability of this amino acid sequence greatly restricted the generation of subunits. However, when the signal sequence was removed, abundantly expressed subunits formed inactive inclusion bodies that could not be assembled into the hexameric native form, although the inclusion body subunits could be refolded and the biological activity recovered in vitro. Therefore, the dilemma choice of signal sequence formed bottlenecks in the expression of LTm. These results reveal the expression bottlenecks of LTm, provide guidance for the preparation of LTm and its subunits, and certainly help to promote efficient preparation of this mucosal adjuvant protein.

The Fabrication of High-Aspect-Ratio Cylindrical Nano Tool using ECM

Yufeng Wang,Ningsong Qu,Yongbin Zeng,Xiujuan Wu,Di Zhu 한국정밀공학회 2013 International Journal of Precision Engineering and Vol. No.

With the miniaturization of various types of components and devices, micro- and nanometer-scale tools are increasingly in demand. Electrochemical machining (ECM) is a well-established technique for the fabrication of micro tools and nano tips. This paper presents a machining method for the fabrication of a high-aspect-ratio cylindrical nano tool using liquid membrane ECM, in which a straight reciprocating motion is applied to the anodic electrode. The method is based on periodic machining of the anodic rod within the amplitude of the straight reciprocating motion. In this process, the machining rate within amplitude varies periodically, allowing nano tools with high aspect ratios to be obtained by the presented method. Experiments were conducted to verify the proposed method. The influences of applied voltage, electrolyte concentration, amplitude and velocity of the straight reciprocating motion on the fabrication of cylindrical nano-electrode were investigated. By using this method, nano-electrodes with average diameters of several hundred nanometers and aspect ratios up to 70 were successfully fabricated.

A Mononuclear Non-Heme Manganese(IV)–Oxo Complex Binding Redox-Inactive Metal Ions

Chen, Junying,Lee, Yong-Min,Davis, Katherine M.,Wu, Xiujuan,Seo, Mi Sook,Cho, Kyung-Bin,Yoon, Heejung,Park, Young Jun,Fukuzumi, Shunichi,Pushkar, Yulia N.,Nam, Wonwoo American Chemical Society 2013 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.135 No.17

<P>Redox-inactive metal ions play pivotal roles in regulating the reactivities of high-valent metal–oxo species in a variety of enzymatic and chemical reactions. A mononuclear non-heme Mn(IV)–oxo complex bearing a pentadentate N<SUB>5</SUB> ligand has been synthesized and used in the synthesis of a Mn(IV)–oxo complex binding scandium ions. The Mn(IV)–oxo complexes were characterized with various spectroscopic methods. The reactivities of the Mn(IV)–oxo complex are markedly influenced by binding of Sc<SUP>3+</SUP> ions in oxidation reactions, such as a ∼2200-fold increase in the rate of oxidation of thioanisole (i.e., oxygen atom transfer) but a ∼180-fold decrease in the rate of C–H bond activation of 1,4-cyclohexadiene (i.e., hydrogen atom transfer). The present results provide the first example of a non-heme Mn(IV)–oxo complex binding redox-inactive metal ions that shows a contrasting effect of the redox-inactive metal ions on the reactivities of metal–oxo species in the oxygen atom transfer and hydrogen atom transfer reactions.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2013/jacsat.2013.135.issue-17/ja312113p/production/images/medium/ja-2012-12113p_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja312113p'>ACS Electronic Supporting Info</A></P>