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( Shi Kun Zhang ),( Qian Ma ),( Su Bo Li ),( Hong Wei Gao ),( Ying Xia Tan ),( Feng Gong ),( Shou Ping Ji ) 한국미생물 · 생명공학회 2016 Journal of microbiology and biotechnology Vol.26 No.6
RV-23 is a melittin-related antibacterial peptide (MRP) with lower cytotoxicity than either melittin or AR-23, another MRP. The aim of this study was to explore the mechanism of RV- 23`s antibacterial selectivity and its hemocompatibility. The results showed that all the peptides exhibited lytic activity against Staphylococcus aureus and Escherichia coli, with RV-23 showing the highest potency. Moreover, RV-23 had lower cytotoxicity than melittin or AR-23 at their minimal inhibitory concentration. In addition, CD experiments showed that melittin, RV-23, and AR-23 all had a typical α-helical structure, and RV-23 had the lowest α-helix content. The structural information showed that RV-23 has the lowest hydrophobicity and highest hydrophobic moment. Because hydrophobicity and α-helix content are believed to correlate with hemolysis, the results indicate that the selective lytic activity against bacteria of RV-23 may be due to its low hydrophobicity and α-helicity, which lead to low cytotoxicity without affecting antibacterial activity. Furthermore, RV-23 did not affect the structure and function of blood components such as red blood cells, platelets, albumin, and the blood coagulation system. In conclusion, RV-23 is a cell-selective antibacterial peptide with high hemocompatibility due to its unique structure.
Xiao Tang,Kun Tong,Lishan Zhu,Guoqing Fu,Wei Chang,Ting Zhou,Zhibing Zhang,Ling Tong,Ling Zhang,Yuqin Shi,Ling Zhang,Yuqin Shi 대한독성 유전단백체 학회 2016 Molecular & cellular toxicology Vol.12 No.4
Di-2-ethylhexyl phthalate (DEHP) which belongs to phthalatic-acid esters, is a kind of harmful, global environmental pollutants. It is a known endocrine disrupting chemical and male reproductive toxicant. However, the mechanism by which DEHP exposure result in male reproductive toxicity is still unclear. To elucidate the productive toxicity mechanism of DEHP, we attemptted to investigate oxidative stress, apoptotic effects, mRNA and protein expression of apoptosis-associated genes including FasL, caspase-3, and caspase-8 in GC-2spd (mouse spermatogenic cells). The results showed that, with the increase of DEHP concentration, cell apoptosis rate increased; the activities of relation index of oxidative stress such as malondialdehyde (MDA), superoxide dismutase (SOD) and glutatione peroxidase (GSH-PX) changed significantly; the mRNA and protein expression levels of FasL, caspase-3, -8, altered obviously. These results suggested that DEHP could induce apoptosis of GC-2spd cells through oxidative stress and FasL-dependent pathway.
A parameterized model of fixed joint interface based on virtual material
Kun Shi,Guangpeng Zhang 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.11
To improve the application simplicity of the research outcomes of fixed joint interface characteristics from mechanical structural numerical analysis, we proposed a parameterized model of a fixed joint interface based on virtual material. Based on the GreenwoodWilliamson contact model, Hertz-Mindilin contact theory, characteristic study of fixed joint interface in the unit area, and considering the impacts of various factors of contacting surfaces, we obtained the virtual material parameters of a fixed joint interface: Elastic modulus, Poisson’s ratio, thickness, and density. Focusing on a mechanical structure with bolt connections, we carried out a numerical analysis of the structural deformation under various loading applications, and compared the analysis results with experimental measurements to validate the feasibility and accuracy of the virtual material parameters of the fixed joint interface. This research lays a foundation for further study of the whole character of mechanical structures.
Shi, Shengbin,Wang, Hang,Uddin, Mohammad Afsar,Yang, Kun,Su, Mengyao,Bianchi, Luca,Chen, Peng,Cheng, Xing,Guo, Han,Zhang, Shiming,Woo, Han Young,Guo, Xugang American Chemical Society 2019 Chemistry of materials Vol.31 No.5
<P>A planar backbone conformation is essential for enabling polymer semiconductors with high charge carrier mobility in organic thin-film transistors. Benefiting from the smaller van der Waals radius of the O atom in furan (versus the S atom in thiophene), alkylated furan exerts a reduced steric hindrance on neighboring arene, and it was found that the head-to-head (HH)-linked 3,3′-dialkyl-2,2′-bifuran (<B>BFR</B>) can attain a high degree of backbone planarity. Hence, <B>BFR</B> should be a promising building block for constructing polymer semiconductors with a planar backbone conformation and hold distinctive advantages over a dialkylbithiophene-based analogue, which is typically highly twisted. The alkyl chains on the 3 and 3′ positions offer good solubility to the resulting polymers, which in combination with its planar backbone yields an improved molecular design window for developing high-performance polymer semiconductors, particularly those with a simple molecular structure and based on the acceptor co-unit without any solubilizing chains. When incorporated into polymer semiconductors, remarkably high hole and electron mobilities of 1.50 and 0.31 cm<SUP>2</SUP> V<SUP>-1</SUP> s<SUP>-1</SUP> are obtained for <B>BFR</B>-based polymers <B>FBFR-BO</B> and <B>CNBFR-C18</B> containing fluorinated and cyano-functionalized benzothiadiazole as the acceptor co-unit, respectively. Such mobilities are the highest values for HH-linked polymers and also among the best for furan-containing polymers. The results demonstrate that HH-linked dialkylbifuran is a highly promising building block for constructing organic and polymeric semiconductors, and this new approach by incorporating HH <B>BFR</B> offers several distinctive advantages for developing high-performance polymer semiconductors, including effective optoelectronic property tuning using a minimal number of aromatic rings, reduced structural complexity, facile material synthesis, good material solubility, and enriching the material library. In addition, the study offers important guidelines for future development of furan-based polymers and head-to-head linkage containing organic semiconductors.</P> [FIG OMISSION]</BR>
Development of a position sensitive CsI(Tl) crystal array
Shi, Guo-Zhu,Chen, Ruo-Fu,Chen, Kun,Shen, Ai-Hua,Zhang, Xiu-Ling,Chen, Jin-Da,Du, Cheng-Ming,Hu, Zheng-Guo,Fan, Guang-Wei Korean Nuclear Society 2020 Nuclear Engineering and Technology Vol.52 No.4
A position-sensitive CsI(Tl) crystal array coupled with the multi-anode position sensitive photomultiplier tube (PS-PMT), Hamamatsu H8500C, has been developed at the Institute of Modern Physics. An effective, fast, and economical readout circuit based on discretized positioning circuit (DPC) bridge was designed for the 64-channel multi-anode flat panel PSPMT. The horizontal and vertical position resolutions are 0.58 mm and 0.63 mm respectively for the 1.0 × 1.0 × 5.0 ㎣ CsI(Tl) array, and the horizontal and vertical position resolutions are 0.86 mm and 0.80 mm respectively for the 2.0 × 2.0 × 10.0 ㎣ CsI(Tl) array. These results show that the CsI(Tl) crystal array with low cost could be applied in the fields of medical imaging and high-resolution gamma camera.
Gut Microbiome Alterations and Functional Prediction in Chronic Spontaneous Urticaria Patients
( Xinyue Zhang ),( Jun Zhang ),( Zhaowei Chu ),( Linjing Shi ),( Songmei Geng ),( Kun Guo ) 한국미생물생명공학회(구 한국산업미생물학회) 2021 Journal of microbiology and biotechnology Vol.31 No.5
The effects of the gut microbiome on both allergy and autoimmunity in dermatological diseases have been indicated in several recent studies. Chronic spontaneous urticaria (CSU) is a disease involving allergy and autoimmunity, and there is no report detailing the role of microbiota alterations in its development. This study was performed to identify the fecal microbial composition of CSU patients and investigate the different compositions and potential genetic functions on the fecal microbiota between CSU patients and normal controls. The gut microbiota of CSU patients and healthy individuals were obtained by 16s rRNA massive sequencing. Gut microbiota diversity and composition were compared, and bioinformatics analysis of the differences was performed. The gut microbiota composition results showed that Firmicutes, Bacteroidetes, Proteobacteria, and Verrucomicrobia were dominant microbiota in CSU patients. The differential analysis showed that relative abundance of the Proteobacteria (p = 0.03), Bacilli (p = 0.04), Enterobacterales (p = 0.03), Enterobacteriaceae (p = 0.03) was significantly increased in CSU patients. In contrast, the relative abundance of Megamonas, Megasphaera, and Dialister (all p < 0.05) in these patients significantly decreased compared with healthy controls. The different microbiological compositions impacted normal gastrointestinal functions based on function prediction, resulting in abnormal pathways, including transport and metabolism. We found CSU patients exhibited gut microbiota dysbiosis compared with healthy controls. Our results indicated CSU is associated with gut microbiota dysbiosis and pointed out that the bacterial taxa increased in CSU patients, which might be involved in the pathogenesis of CSU. These results provided clues for future microbial-based therapies on CSU.
Sha Liao,Shi-Yong Fan,Qin Liu,Chang-Kun L,Jia Chen,Jing-Lai Li,Zhi-Wei Zhang,Zhen-Qing Zhang,Bo-Hua Zhong,Jian-Wei Xie 대한약학회 2014 Archives of Pharmacal Research Vol.37 No.11
Chronic hepatitis B virus (HBV) infection maylead to liver cirrhosis and hepatocellular carcinoma, butfew drugs are available for its treatment. Acyclic nucleosidephosphonates (ANPs) have remarkable antivirusactivities but are not easily absorbed from the gastrointestinaltract and accumulate in the kidneys, resulting innephrotoxicity. Therefore, there is a need to find effectiveliver site-specific prodrugs. The dipivaloyloxymethyl esterof 9-(2-phosphonylmethoxyethyl)adenine (PMEA)—adefovirdipivoxil (ADV)—is a first-line therapy drug forchronic hepatitis B with a low therapeutic index because ofrenal toxicity and low hepatic uptake. In this study, a seriesof PMEA derivatives were synthesized to enhance plasmastability and liver release. The metabolic stability of ADV(Chemical I) and its two analogues (Chemicals II and III)was evaluated in rat plasma and liver homogenate in vitro. An ion-pair reverse-phase HPLC–UV method and a hybridion trap and high-resolution time-of-flight mass spectrometry(LC-IT-TOF-MS) were used to evaluate the degradationrate of the analogues and to identify their intermediatemetabolites, respectively. Chemicals I and II were hydrolyzedby cleavage of the C–O bond to give monoesters. Sufficient enzymatic activation in the liver homogenatethrough a relatively simple metabolic pathway, in additionto a favorable stability profile in rat plasma, made ChemicalII an optimal candidate. Next, six analogues based onthe structure of Chemical II were synthesized and evaluatedin plasma and liver homogenate. Compared toChemical II, these compounds generated less active PMEAlevels in rat liver homogenate. Therefore, chemical modificationof Chemical II may lead to new promising PMEAderivatives with enhanced plasma stability and liveractivation.