Stabilization of Polymer-Hydrogel Capsules via Thiol–Disulfide Exchange

Chong, Siow-Feng,Chandrawati, Rona,Stä,dler, Brigitte,Park, Jeongju,Cho, Jinhan,Wang, Yajun,Jia, Zhongfan,Bulmus, Volga,Davis, Thomas P.,Zelikin, Alexander N.,Caruso, Frank WILEY-VCH Verlag 2009 Small Vol.5 No.22

<P>Polymer hydrogels are used in diverse biomedical applications including drug delivery and tissue engineering. Among different chemical linkages, the natural and reversible thiol–disulfide interconversion is extensively explored to stabilize hydrogels. The creation of macro-, micro-, and nanoscale disulfide-stabilized hydrogels commonly relies on the use of oxidizing agents that may have a detrimental effect on encapsulated cargo. Herein an oxidization-free approach to create disulfide-stabilized polymer hydrogels via a thiol–disulfide exchange reaction is reported. In particular, thiolated poly(methacrylic acid) is used and the conditions of polymer crosslinking in solution and on colloidal porous and solid microparticles are established. In the latter case, removal of the core particles yields stable, hollow, disulfide-crosslinked hydrogel capsules. Further, a procedure is developed to achieve efficient disulfide crosslinking of multilayered polymer films to obtain stable, liposome-loaded polymer-hydrogel capsules that contain functional enzymatic cargo within the liposomal subcompartments. This approach is envisaged to facilitate the development of biomedical applications of hydrogels, specifically those including fragile cargo.</P> <B>Graphic Abstract</B> <P>Polymer-hydrogel capsules are stabilized via disulfide linkages whereby crosslinking relies on the thiol–disulfide exchange without the use of oxidizing agents (see image). The method permits the formation of hollow capsules as well as functional capsosomes, hydrogel capsules subcompartmentalized with enzyme-loaded liposomes, without the loss of activity of liposome-encapsulated enzymes. <img src='wiley_img/16136810-2009-5-22-SMLL200900906-content.gif' alt='wiley_img/16136810-2009-5-22-SMLL200900906-content'> </P>

Paleoenvironmental changes of source rocks from the Carboniferous to Permian sediments of the Mahu Sag, Junggar Basin, China

Feng Chong,Ma Mingze,He Wenjun,Li Teng,Wu Qiuyu,Zhang Zexin,Zhao Haiyang 한국자원공학회 2020 Geosystem engineering Vol.23 No.5

There are four sets of source rocks from Carboniferous (C) to Permian in Mahu Sag, and the paleoenvironment is the decisive factor for the differences of source rocks. In order to study the controlling effect of paleoenvironmental evolution on the change of source rock properties, the major, trace elements and the total organic carbon (TOC) of 47 core samples from four sets of source rocks were tested. The results indicate that the paleoenvironmental evolution of these four sets of source rocks from C to Permian in Mahu Sag can be divided into five stages. At the end of C and the early stage of deposition of Wuerhe formation (P2w), the paleo climate became warm and humid, and the salinity of water body became small. Meanwhile, the oxidizability of water body gradually became stronger. At the deposition stage of Jiamuhe Formation (P1j), Fengcheng Formation (P1f) and the late stage of deposition of P2w, the paleo climate gradually became hot and dry, and the salinity of water body gradually increased. Meanwhile, the reducibility of water body became stronger. The paleoenvironmental factors controlling the abundance of organic matter in source rocks are different in different stages.

Centrifuge Modelling and Analysis of Ground Reaction of High-speed Railway Embankments over Medium Compressibility Ground

Chong-lei Zhang,Guan-lu Jiang,Xian-feng Liu,Li-jun Su 대한토목학회 2018 KSCE Journal of Civil Engineering Vol.22 No.12

The objective of this study is to verify the feasibility of using centrifugal model tests to characterize the ground reaction response of a high-speed railway embankment to predict its ground settlement. To do so, a series of Centrifugal Model Tests (CMTs) of the embankment were performed to investigate the variation of ground reaction and corresponding derived modulus at different embankment ratios. The ground reaction determined from the CMTs was compared with those obtained from corresponding fullscale field tests of instrumented embankment. The results show that the ground reaction at the embankment centreline gradually approaches the embankment weight (γH) with increasing embankment ratio. Considering the embankment filling process with different embankment ratios, it seems inappropriate to employ the value of γH as the ground reaction without any correction in settlement prediction. Finally, the predictive capability of the proposed approach for embankment settlement estimation was assessed against the corresponding field measurements and those determined based on the calculation methods suggested in the current design standard in China. The results show that the proposed simple approach satisfactorily estimates the ground settlement of HSR embankments and its deviation of predicted settlements is below 11.9% compared with the data obtained from the field full-scale tests. However, the deviation of the result calculated by the current recommend design standard is 17.7%-148.3%.

Artemongolins A–K, undescribed germacrane-guaiane sesquiterpenoid dimers from Artemisia mongolica and their antihepatoma activities

Chong Shang,Yun-Bao Ma,Yuan Wang,Xiao-Feng He,Tian-Ze Li,Ji-Jun Chen 대한약학회 2023 Archives of Pharmacal Research Vol.46 No.10

Artemongolins A–K (1–11), which are undescribed sesquiterpenoid dimers, were obtained from Artemisia mongolica and characterized through comprehensive spectral data, including HRESIMS, IR, 1D and 2D NMR, and ECD calculations. The absolute configurations of compounds 1, 4, and 7 were undoubtedly determined by a single-crystal X-ray crystallography. Artemongolins A–K (1–11) featured a rare 5/7/5/5/5/10 hexacyclic system composed of a germacrene and a guaianolide by a fused 2-oxaspiro[4,4]nonane-1-one ring system. Antihepatoma evaluation against three human hepatoma cell lines demonstrated that the most active compounds 5 and 6 displayed inhibitory activity with IC50 values of 88.6 and 57.0 (HepG2), 59.1 and 26.4 (Huh7), and 67.5 and 32.5 (SK-Hep-1) µM, respectively.

Influences of Sputtering Gas Pressure and Gas Flow Rate on Microwave Characteristics of FeCoAlO Thin Films

Feng Xu,Nyugen Nyugen Phuoc,Chong Kim Ong 한국자기학회 2010 한국자기학회 학술연구발표회 논문개요집 Vol.2010 No.12

Ginseng berry polysaccharides on infl ammation-associated colon cancer: inhibiting T-cell differentiation, promoting apoptosis, and enhancing the effects of 5-fl uorouracil

Chong-Zhi Wang,Lifei Hou,Jin-Yi Wan,Haiqiang Yao,Jinbin Yuan,Jinxiang Zeng,Chan Woong Park,Su Hwan Kim,Dae Bang Seo,Kwang-Soon Shin,Chun-Feng Zhang,Lina Chen,Qi-Hui Zhang,Zhi Liu,Clara Sava-Segal,Chun 고려인삼학회 2020 Journal of Ginseng Research Vol.44 No.2

Background: Ginseng is a commonly used herbal medicine in treating various medical conditions. Chronic gut inflammation is a recognized factor for the development of colorectal cancer (CRC). In thisproject, Asian ginseng berry polysaccharide preparations were used to assess their effects on CRC andrelated immune regulation mechanisms. Methods: Ginseng berry polysaccharide extract (GBPE) and purified ginseng berry polysaccharideportion (GBPP) were used to evaluate their activities on human HCT-116 and HT-29 CRC cell proliferation. Interleukin-8 secretion analysis was performed on HT-29 cells. Naive CD4 cell isolation and T-helper celldifferentiation were performed and determined using flow cytometry for Th1 and Treg in addition to cellcycle and apoptotic investigation. Results: GBPE and GBPP significantly inhibited interleukin-8 secretion and cancer cell proliferation,inhibited CD4þIFN-gþ cell (Th1) differentiation, and decreased CD4þFoxP3þ cell (Treg) differentiation. Compared to the GBPE, GBPP showed more potent antiinflammatory activities on the malignant cells. This is consistent with the observation that GBPP can also inhibit Th1-cell differentiation better, suggestingthat it has an important role in antiinflammation, whereas Treg cells hinder the body’s immuneresponse against malignancies. Supported by cell cycle and apoptosis data, GBPE and GBPP, at variousdegrees, remarkably enhanced the anticancer activities of 5-fluorouracil. Conclusion: Data from this project suggested that Asian ginseng berry potentially has clinical utility inmanaging enteric inflammation and suppressing CRC through immunomodulation mechanisms.

Identifi cation of key leaf color-associated genes in Gleditsia sinensis using bioinformatics

Chong Wu,Xuemei Yang,Lijuan Feng,Fei Wang,Haixia Tang,Yanlei Yin 한국원예학회 2019 Horticulture, Environment, and Biotechnology Vol.60 No.5

This study aimed to explore leaf-color associated genes in Gleditsia sinensis ( G. sinensis ) using bioinformatics methods. Green, purple, and yellow leaves were collected from G. sinensis in Shandong Institute of Pomology. Total RNA was collectedfrom leaves and subjected to transcriptome sequencing. Diff erentially expressed genes (DEGs) were identifi ed amongthe diff erent colored leaves using RSEM method followed by functional enrichment analysis. Finally, qRT-PCR analysis wasused to assess the expression of several pigment-related genes enriched in signifi cant GO or KEGG terms. A total of 10,953,14,961, and 8916 DEGs were identifi ed between green vs. purple leaves, green vs. yellow leaves, and purple vs. yellow leaves,respectively. Among the green vs. purple leaves, DEGs were signifi cantly enriched in terms of iron ion binding, tetrapyrrolebinding, (e.g., CYP26A1 , CYP97A3 , and CYP86A1 ), and starch and sucrose metabolism (e.g., TPS and VTC2 ). DEGsfor green/purple vs. yellow groups were markedly enriched in circadian rhythm-plant KEGG pathway, including ELF3 andCHS . Compared with their expression in green leaves, CYP26A1 , CYP97A3 , CYP86A1 , TPS and VTC2 were signifi cantlydownregulated in purple leaves, while downregulation of ELF3 and upregulation of CHS was detected in yellow leaves. CYPs (e.g., CYP26A1 and CYP97A3 ) might play critical roles in the determination of leaf color in G. sinensis via iron ionand tetrapyrrole binding. In addition, genes related to starch and sucrose metabolism (e.g., TPS and VTC2 ), and circadianrhythms (e.g., ELF3 and CHS ) might also be involved in controlling leaf color.

Effects of Ohmic Area Etching on Buffer Breakdown Voltage of AlGaN/GaN HEMT

Chong Wang,Xiao-Xiao Wel,Meng-Di Zhao,Yun-Long He,Xue-Feng Zheng,Wei Mao,Xiao-Hua Ma,Jin-Cheng Zhang,Yue Hao 한국전기전자재료학회 2017 Transactions on Electrical and Electronic Material Vol.18 No.3

This study is on how ohmic area etching affects the buffer breakdown voltage of AlGaN/GaN HEMT. The surfacemorphology of the ohmic metal can be improved by whole etching on the ohmic area. The buffer breakdown voltagesof the samples with whole etching on the ohmic area were improved by the suppression of the metal spikes formedunder the ohmic contact regions during high-temperature annealing. The samples with selective etching on theohmic area were investigated for comparison. In addition, the buffer leakage currents were measured on the differentradii of the wafer, and the uniformity of the buffer leakage currents on the wafer were investigated by PL mappingmeasurement.

Effects of Ohmic Area Etching on Buffer Breakdown Voltage of AlGaN/GaN HEMT

Wang, Chong,Wel, Xiao-Xiao,Zhao, Meng-Di,He, Yun-Long,Zheng, Xue-Feng,Mao, Wei,Ma, Xiao-Hua,Zhang, Jin-Cheng,Hao, Yue The Korean Institute of Electrical and Electronic 2017 Transactions on Electrical and Electronic Material Vol.18 No.3

This study is on how ohmic area etching affects the buffer breakdown voltage of AlGaN/GaN HEMT. The surface morphology of the ohmic metal can be improved by whole etching on the ohmic area. The buffer breakdown voltages of the samples with whole etching on the ohmic area were improved by the suppression of the metal spikes formed under the ohmic contact regions during high-temperature annealing. The samples with selective etching on the ohmic area were investigated for comparison. In addition, the buffer leakage currents were measured on the different radii of the wafer, and the uniformity of the buffer leakage currents on the wafer were investigated by PL mapping measurement.

An alternatively spliced form of Met receptor is tumorigenic

이재호,Chong Feng Gao,Chong Chou Lee,김명덕,George F. Vande Woude 생화학분자생물학회 2006 Experimental and molecular medicine Vol.38 No.5

The Met tyrosine kinase receptor is a widely expressed molecule, which mediates pleiotropic celular responses following activation by its ligand, hepatocyte growth factor/scatter factor (HGF/SF). Previously, one of the authors identified an alter-natively spliced form of Met (Met-SM) that lacked a single exon of a 47-amino-acid segment in the juxtamembrane domain. Here we report that Met-SM is a potent transforming gene in NIH3T3 mouse fibroblast cells. Met-SM-transfected NIH3T3 cells show stronger foci-forming activity than wild type- Met-transfected ones. In addition, Met-SM-trans-tumorigenic in athymic nu/nu mice. Furthermore, HGF/SF significantly increases the focus-forming activity of Met-SM comparing to wild type Met. The amount of protein and of tyrosine kinase activity of Met-SM accumulates to a high level following HGF/SF treatment. The accumulation of Met-SM correlated well with its delayed ubiquitination and increased stability. These results are consistent with the important role of the juxtamembrane domain in protein stability of Met receptor and suggest that the alternatively-spliced form may contribute to the development and progression of human cancer.