Microstructure and mechanical properties of carbon graphite composites reinforced by carbon nanofibers

Chen Yixing,Tu Chuanjun,Liu Yanli,Liu Ping,Gong Pei,Wu Guangning,Huang Xia,Chen Jian,Liu Tianhua,Jiang Jizhou 한국탄소학회 2023 Carbon Letters Vol.33 No.2

Renewed interest in the reinforced carbon graphite composites has intrigued the community in the advanced materials fields. In this work, we present a simple carbon nanofibers reinforced carbon graphite composites synthetic method by incorporating mixture of coal tar pitch, synthetic graphite, pitch coke and the dispersion liquid of carbon nanofibers via liquid-phase mixing process. The impact of carbon nanofiber utilization on the microstructures and mechanical properties of carbon graphite composites are studied systematically. The covalent surface modification of carbon nanofibers effectively improves its microstructure and thereby promotes the carbon graphite composites’ dispersion behavior. We propose that a small amount of carbon nanofibers could promote the carbonization process of carbon graphite composites, facilitating the densification of carbon graphite composites and reducing the undesired open porosity. The amount of 0.7 wt % of carbon nanofiber concentration allows the enhancement of bend and compressive strength of carbon graphite composites up to 36.50 MPa and 60.46 MPa, increased by 167.9% and 146.9% compared with the pure carbon graphite composite, respectively. Our findings can be rationalized due to the improvement in the mechanical strength of carbon graphite composites could be attributed due to pull-out of carbon nanofibers from the matrix and bridging effect across the crack pores within the matrix.

직무스트레스 요인과 감정노동의 직무만족과의 관계에서 직무소진의 매개 효과 및 사회적 지원의 조절 효과 연구

김일성(Jin Yixing),송계충(Kye Chung Song) 한국인적자원개발학회 2012 인적자원개발연구 Vol.15 No.2

블로그 사용에 영향을 미치는 요인

권오병(Ohbyung Kwon),문예성(Yixing Wen),김민용(Minyong Kim) 한국전자거래학회 2007 한국전자거래학회지 Vol.12 No.4

블로그는 정보 공유와 관계 형성의 유력한 미디어로 인정되고 있다. 그러나 기존의 기술수용 모델은 블로그와 같은 관계 지향적인 정보시스템에 대한 수용성을 설명하는 데 적합한지 증명되지 않은 상태이다. 따라서 본 연구의 목적은 블로그 사용에 영향 주는 요인을 규명하는 것이다. 이것을 위해 유력한 포털사이트인 네이버 블로거들을 대상으로 인지된 유용성, 인지된 격려와 실제사용의 인과 관계를 대중적 자기 인식, 자기노출과 텔레프레즌스를 변수로 검증하였다. 그 결과, 대중적 자기인식과 자기노출은 인지된 유용성과 인지된 격려의 유의미한 요인으로 보여지고 인지된 유용성과 인지된 격려는 블로그의 실제사용에 유의미한 영향을 주는 것으로 보여졌다. Recently, blogging has been regarded as a promising media for information sharing and relationship building. However, it is not quite sure if the technology acceptance model could be completely adopted also in relationship-based system such as blog. Hence, the purpose of this paper is to identify the factors affecting the usage of blogs. To do so, content analysis methodology is applied to extract meaningful factors affecting the usage of blogs in the opinions of the bloggers in a Korean portal site : Naver. We investigates the causal relationship among three factors ; perceived usefulness, perceived encouragement, and actual use in blogging. Moreover, public self-consciousness, self disclosure and telepresence are also considered as the determinants. The results show that public selfconsciousness and self disclosure are significant elements affecting perceived usefulness and perceived encouragement, while perceived usefulness and perceived encouragement both affecting the actual use of blogs.

Clenbuterol Inhibits SREBP-1c Expression by Activating CREB1

Zhou, Lei,Li, Yixing,Nie, Tao,Feng, Shengqiu,Yuan, Jihong,Chen, Huaping,Yang, Zaiqing Korean Society for Biochemistry and Molecular Biol 2007 Journal of biochemistry and molecular biology Vol.40 No.4

As a $\beta_2$-adrenergic agonist, clenbuterol decreases body fat, but the molecular mechanism underlying this process is unclear. In the present study, we treated 293T and L-02 cells with clenbuterol and found that clenbuterol downregulates SREBP-1c expression and upregulates CREB1 expression. Considering SREBP-1c has the function of regulating the transcription of several lipogenic enzymes, we considered that the downregulation of SREBP-1c is responsible for body fat reduction by clenbuterol. Many previous studies have found that clenbuterol markedly increases intracellular cAMP levels, therefore, we also investigated whether CREB1 is involved in this process. The data from our experiments indicate that CREB1 overexpression inhibits SREBP-1c transcription, and that this action is antagonized by CREB2, a competitive inhibitor of CREB1. Furthermore, since PPARs are able to repress SREBP-1c transcription, we investigated whether clenbuterol and CREB1 function via a pathway involving PPAR activation. However, our results showed that clenbuterol or CREB1 overexpression suppressed PPARs transcription in 293T and L-02 cells, which suggested that they impair SREBP-1c expression in other ways.

A new model and testing verification for evaluating the carbon efficiency of server

Liang Guo,Yue Wang,Yixing Zhang,Caihong Zhou,Kexin Xu,Shaopeng Wang 한국인터넷정보학회 2023 KSII Transactions on Internet and Information Syst Vol.17 No.10

To cope with the risks of climate change and promote the realization of carbon peaking and carbon neutrality, this paper first comprehensively considers the policy background, technical trends and carbon reduction paths of energy conservation and emission reduction in data center server industry. Second, we propose a computing power carbon efficiency of data center server, and constructs the carbon emission per performance of server (CEPS) model. According to the model, this paper selects the mainstream data center servers for testing. The result shows that with the improvement of server performance, the total carbon emissions are rising. However, the speed of performance improvement is faster than that of carbon emission, hence the relative carbon emission per unit computing power shows a continuous decreasing trend. Moreover, there are some differences between different products, and it is calculated that the carbon emission per unit performance is 20-60KG when the service life of the server is five years.

Identification and heterologous reconstitution of a 5-alk(en)ylresorcinol synthase from endophytic fungus Shiraia sp. Slf14

Huiwen Yan,Lei Sun,Jinge Huang,Yixing Qiu,Fuchao Xu,Riming Yan,Du Zhu,Wei Wang,Jixun Zhan 한국미생물학회 2018 The journal of microbiology Vol.56 No.11

A new type III polyketide synthase gene (Ssars) was discovered from the genome of Shiraia sp. Slf14, an endophytic fungal strain from Huperzia serrata. The intron-free gene was cloned from the cDNA and ligated to two expression vectors pET28a and YEpADH2p-URA3 for expression in Escherichia coli BL21(DE3) and Saccharomyces cerevisiae BJ5464, respectively. SsARS was efficiently expressed in E. coli BL21(DE3), leading to the synthesis of a series of polyketide products. Six major products were isolated from the engineered E. coli and characterized as 1,3-dihydroxyphenyl- 5-undecane, 1,3-dihydroxyphenyl-5-cis-6 -tridecene,1,3-dihydroxyphenyl- 5-tridecane, 1,3-dihydroxyphenyl-5-cis-8 - pentadecene, 1,3-dihydroxyphenyl-5-pentadecane, and 1,3- dihydroxyphenyl-5-cis-10 -heptadecene, respectively, based on the spectral data and biosynthetic origin. Expression of SsARS in the yeast also led to the synthesis of the same polyketide products, indicating that this enzyme can be reconstituted in both heterologous hosts. Supplementation of soybean oil into the culture of E. coli BL21(DE3)/SsARS increased the production titers of 1–6 and led to the synthesis of an additional product, which was identified as 5-(8 Z,11 Z-heptadecadienyl) resorcinol. This work thus allowed the identification of SsARS as a 5-alk(en)ylresorcinol synthase with flexible substrate specificity toward endogenous and exogenous fatty acids. Desired resorcinol derivatives may be synthesized by supplying corresponding fatty acids into the culture medium.

Analysis of influencing parameters and reactive substance for enrofloxacin degradation in a dielectric barrier discharge plasma/peroxydisulfate system

Shilin Song,Huijuan Wang,Yuyue Huang,Yixing Ma 대한환경공학회 2024 Environmental Engineering Research Vol.29 No.4

In this paper, the chemical and physical effects generated during the dielectric barrier discharge plasma (DBDP) process, including O₃, H₂O₂, light, e<SUP>*</SUP>, etc., were utilized to activate the peroxydisulfate (PDS) to form SO₄<SUP>−</SUP>•. Then, the original reactive oxygen species (ROS), such as •OH, formed in the discharge system was combined to degrade the enrofloxacin (ENR) in water, and the corresponding influencing parameters and reactive substance in the DBDP/PDS system were analyzed. From the investigation, it was found that the neutral (pH =6.5) solution was more conducive to the ENR decomposition than the acidic and alkaline solution conditions. The presence of Fe<SUP>2+</SUP> and Cu<SUP>2+</SUP> in the reaction solution could hasten the ENR degradation, whereas the addition of Cl<SUP>−</SUP> and the HCO₃<SUP>−</SUP> in the solution had a negative effect. Analysis of the reactive species and quenching tests were carried out to explore the generation of H₂O₂, O₃, •OH, and SO₄<SUP>−</SUP>• in the DBDP/PDS system and their effects on the ENR degradation. The UV-Vis and 3D fluorescence spectra analysis were applied to demonstrate the cooperative effects of the DBDP and the PDS. The TOC and COD removals of the ENR solutions in the DBDP and the DBDP/PDS systems were also compared. Based on the intermediates analysis of the ENR degradation, three possible pathways of ENR decomposition in the synergistic system have been inferred.

N6-Methyladenosine modification (m6 A) of circRNA-ZNF638 contributes to the induced activation of SHF stem cells through miR-361-5p/Wnt5a axis in cashmere goats

Yin Ronghuan,Yin Ronglan,Bai Man,Fan Yixing,Wang Zeying,Zhu Yubo,Zhang Qi,Hui Taiyu,Shen Jincheng,Feng Siyu,Bai Wenlin 아세아·태평양축산학회 2023 Animal Bioscience Vol.36 No.4

Objective: The objective of this study was to investigate the effects of N6-Methyladenosine modification-circRNA-zinc finger protein 638 (m6A-circRNA-ZNF638) on the induced activation of secondary hair follicle (SHF) stem cells with its potential mechanisms in cashmere goats. Methods: The m6A modification of ZNF638 was analyzed using methylation immunoprecipitation with real-time quantitative polymerase chain reaction technique in SHF stem cells. The effects of circRNA-ZNF638 on the induced activation of SHF stem cells in m6A dependence were evaluated through the overexpression of circRNA-ZNF638/its m6Adeficient mutants in circRNA-ZNF638 knockdown SHF stem cells. The competitive binding of miR-361-5p to circRNA-ZNF638/Wnt5a 3′- untranslated region was analyzed through Dual-luciferase reporter assay. Results: The m6A-circRNA-ZNF638 had significantly higher transcription at anagen SHF bulge of cashmere goats compared with that at telogen, as well as it positively regulated the induced activation of SHF-stem cells in cashmere goats. Mechanismly, m6A-circRNA-ZNF638 sponged miR-361-5p to heighten the transcriptional expression of Wnt5a gene in SHFstem cells. We further demonstrated that the internal m6A modification within circRNAZNF638 is required for mediating the miR-361-5p/Wnt5a pathway to regulate the induced activation of SHF stem cells through an introducing of m6A-deficient mutant of circRNAZNF638. Conclusion: The circRNA-ZNF638 contributes the proper induced activation of SHF-stem cells in cashmere goats in m6A-dependent manner through miR-361-5p/Wnt5a axis.

Effects of Alpha 1- and Alpha 2-Adrenoreceptor Stimulation on Galanin mRNA Expression in Primary Cultured Superior Cervical Ganglion Neurons

( Yi Xing ),( Xiu Ying Chen ),( Zhen Liu ),( Hao Li ),( Hua Xiang Liu ),( Zhen Zhong Li ) 한국응용약물학회 2011 Biomolecules & Therapeutics(구 응용약물학회지) Vol.19 No.3

Galanin (Gal) is a 29-amino-acid neuropeptide which is expressed in superior cervical ganglion (SCG) neurons and plays a trophic role in the adult animal and acts as an inhibitory modulator of cholinergic and noradrenergic neurotransmission. Whether activation or inhibition of alpha-adrenoreceptors infl uences Gal mRNA expression in SCG neurons remains unknown. Here, we have evaluated the possible regulation of Gal mRNA expression with acute (4 h) and chronic (4 days) stimulation of alpha 1- and alpha 2-adrenoreceptor agonists or antagonists in primary cultured SCG neurons. The results showed that the amount of Gal mRNA expression in cultured SCG neurons increased significantly after chronic stimulation with alpha 2-adrenoreceptor antagonist yohimbine compared with control SCG neurons at the same time point, whereas the amount of Gal mRNA expression decreased significantly after chronic stimulation with alpha 2-adrenoreceptor agonist clonidine as compared with that in control group. All these effects were not dose-dependent on the administration of alpha 2-adrenoreceptor agonist clonidine or alpha 2-adrenoreceptor antagonist yohimbine. Alpha 1-adrenoreceptor agonist phenylephrine or antagonist prazosin chronic stimulation did not have effects on Gal mRNA expression. Acute exposure of these agents did not have effects on Gal mRNA expression. The present study showed that Gal may be regulated by activation or inhibition of alpha 2-adrenoreceptors, but not alpha 1-adrenoreceptors in sympathetic neurons.