Effect of oxidizing treatment on electrocatalytic activity of boron-doped amorphous carbon thin films

Wang Chen-Song,Suo Ni,Huang Hao,Wu Ai-min,Cao Guo-Zhong,Zhang Gui-Feng 한국탄소학회 2019 Carbon Letters Vol.29 No.5

Boron-doped amorphous carbon (BDAC) thin films with a regular oxygen reduction reaction (ORR) catalytic activity were synthesized in a hot filament chemical vapor deposition device using a mixture of CH4 and H2 as a gas source and B2O3 as a boron source and then oxidized in air at 380–470 °C for 15–75 min. Scanning electron microscope, transmission electron microscope, Raman spectroscopy, X-ray photoelectron spectroscopy, and electrochemical tests were used to characterize the physical and electrochemical properties of the BDAC catalysts. It was concluded that the BDAC catalyst oxidized at 450 °C for 45 min showed the best ORR catalytic activity in alkaline medium. The oxygen reduction potential and the transfer electron number n, respectively, are − 0.286 V versus Ag/AgCl and 3.24 from the rotating disk electrode experiments. The treated carbon film has better methanol resistance and stability than the commercial Pt/C catalyst.

Effect of oxidizing treatment on electrocatalytic activity of boron‑doped amorphous carbon thin films

Chen‑Song Wang,Ni Suo,Hao Huang,Ai‑min Wu,Guo‑Zhong Cao,Gui‑Feng Zhang 한국탄소학회 2019 Carbon Letters Vol.29 No.5

Boron-doped amorphous carbon (BDAC) thin films with a regular oxygen reduction reaction (ORR) catalytic activity were synthesized in a hot filament chemical vapor deposition device using a mixture of CH4 and H2 as a gas source and B2O3 as a boron source and then oxidized in air at 380–470 °C for 15–75 min. Scanning electron microscope, transmission electron microscope, Raman spectroscopy, X-ray photoelectron spectroscopy, and electrochemical tests were used to characterize the physical and electrochemical properties of the BDAC catalysts. It was concluded that the BDAC catalyst oxidized at 450 °C for 45 min showed the best ORR catalytic activity in alkaline medium. The oxygen reduction potential and the transfer electron number n, respectively, are − 0.286 V versus Ag/AgCl and 3.24 from the rotating disk electrode experiments. The treated carbon film has better methanol resistance and stability than the commercial Pt/C catalyst.

FSCB phosphorylation in mouse spermatozoa capacitation

( Shun Li Liu ),( Bing Ni ),( Xiang Wei Wang ),( Wen Qian Huo ),( Jun Zhang ),( Zhi Qiang Tian ),( Ze Min Huang ),( Yi Tian ),( Jun Tang ),( Yan Hua Zheng ),( Feng Shuo Jin ),( Yan Feng Li ) 생화학분자생물학회(구 한국생화학분자생물학회) 2011 BMB Reports Vol.44 No.8

It is generally accepted that spermatozoa capacitation is associated with protein kinase A-mediated tyrosine phosphorylation. In our previous study, we identified the fibrous sheath CABYR binding protein (FSCB), which was phosphorylated by PKA. However, the phosphorylation status of FSCB protein during spermatozoa capacitation should be further investigated. To this aim, in this study, we found that phosphorylation of this 270-kDa protein occurred as early as 1 min after mouse spermatozoa capacitation, which increased over time and remained stable after 60 min. Immunoprecipitation assays demonstrated that the tyrosine and Ser/Thr phosphorylation of FSCB occurred during spermatozoa capacitation. The extent of phosphorylation and was closely associated with the PKA activity and spermatozoa motility characteristics. FSCB phosphorylation could be induced by PKA agonist DB-cAMP, but was blocked by PKA antagonist H-89.Therefore, FSCB contributes to spermatozoa capacitation in a tyrosine-phosphorylated format, which may help in further elucidating the molecular mechanism of spermatozoa capacitation. [BMB reports 2011; 44(8): 541-546]

Distinctive Roles of Wnt Signaling in Chondrogenic Differentiation of BMSCs under Coupling of Pressure and Platelet-Rich Fibrin

Cheng Baixiang,Feng Fan,Shi Fan,Huang Jinmei,Zhang Songbai,Quan Yue,Tu Teng,Liu Yanli,Wang Junjun,Zhao Ying,Zhang Min 한국조직공학과 재생의학회 2022 조직공학과 재생의학 Vol.19 No.4

BACKGROUND: Although newly formed constructs of feasible pressure-preadjusted bone marrow mesenchymal stem cells (BMSCs) and platelet-rich fibrin (PRF) showed biomechanical flexibility and superior capacity for cartilage regeneration, it is still not very clear how BMSCs and seed cells feel mechanical stimuli and convert them into biological signals, and the difference in signal transduction underlying mechanical and chemical cues is also unclear. METHODS: To determine whether mechanical stimulation (hydrostatic pressure) and chemical cues (platelet-rich fibrin, PRF) activate canonical or noncanonical Wnt signaling in BMSCs, BMSCs cocultured with PRF were subjected to hydrostatic pressure loading, and the activation of the Wnt signaling molecules and expression of cartilage-associated proteins and genes were determined by western blotting and polymerase chain reaction (PCR). Inhibitors of canonical or noncanonical Wnt signaling, XVX-939 or L690,330, were adopted to investigate the role of Wnt signaling molecules in mechanically promoted chondrogenic differentiation of BMSCs. RESULTS: Hydrostatic pressure of 120 kPa activated both Wnt/b-catenin signaling and Wnt/Ca2? signaling, with the the maximum promotion effect at 60 min. PRF exerted no synergistic effect on Wnt/b-catenin signaling activation. However, the growth factors released by PRF might reverse the promotion effects of pressure on Wnt/Ca2? signaling. Real-time PCR and Western blotting results showed that pressure could activate the expression of Col-II, Sox9, and aggrecan in BMSCs cocultured with PRF. Blocking experiment found a positive role of Wnt/b-catenin signaling, and a negative role of Wnt/ Ca2? signaling in chondrogenic differentiation of the BMSCs. Mutual inhibition exists between canonical and noncanonical Wnt signaling in BMSCs under pressure. CONCLUSION: Wnt signaling participates in the pressure-promoted chondrogenesis of the BMSCs co-cultured with PRF, with canonical and noncanonical pathways playing distinct roles during the process.

Soybean hull functionalized by phosphoric acid for sorption of copper from aqueous solution

Renmin Gong,Lingling Liu,Min Feng,Jiajing Zhao,Xingyan Liu,Shoujun Ni 한국화학공학회 2009 Korean Journal of Chemical Engineering Vol.26 No.2

One kind of potentially biodegradable cationic sorbent, which bears hydroxyl groups of phosphoric acid as its functional groups, with high sorption capacity of copper was prepared by thermochemically esterifying phosphoric acid (PA) onto soybean hull. Sorption of Cu(Ⅱ) from aqueous solution onto modified soybean hull (MSH) was investigated in a batch system. The sorption experiments were performed under various conditions such as different initial pH, copper concentration, MSH dosage, and contact time. The maximum copper sorption was obtained when initial solution pH≥3.5. The isothermal data of copper sorption fitted the Langmuir model and the sorption process could be described by the pseudo-first-order kinetic model. The maximum sorption capacity (Qm) of MSH for Cu(Ⅱ) was 31.55 mg/g. For 100 mg/l of Cu(Ⅱ) solution, a sorption ratio above 91% could be achieved by 5.0 g/l of MSH. The equilibrium of Cu(Ⅱ) sorption was reached within 50 min. The foreign cation and chelator in Cu(Ⅱ) solution caused decline of Cu(Ⅱ) sorption.

Experimental Research on Hole Wall Integrity of TiBw/TC4 Based on Ultrasonic Vibration Assisted Drilling

Yong Feng,Haoxiang Wang,Min Zhang,Zihao Zhu,Xiaoyu Wang,Binhui Jia,Xiaolin Jia 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.21 No.5

Titanium Matrix Composites (TMCs) are widely used in aerospace because of their excellent mechanical properties, but itis accompanied by the diffi culty of machining. Ultrasonic Vibration Assisted Drilling (UVAD) can eff ectively reduce theaxial force in the drilling process and improve the integrity of machined surface. In this paper, the discontinuous titaniummatrix composite TiBw/TC4 was developed by preparation method of in situ. In order to obtain the machining parameters ofTiBw/TC4 and guide the application of UVAD in TiBw/TC4, the contrast experiments between conventional drilling (CD)and UVAD were carried out to analyze the variation law of axial force. In this experiment, the frequency and amplitude ofultrasonic vibration were set as 35 kHz and 2.5 μm respectively, and the drilling conditions were that the spindle speed was(1500/1600/1700/1800/1900) r/min and the feed speed was (6/7/8/9/10) mm/min. The surface integrity of hole wall suchas roughness, residual stress and white layer was discussed. The experimental results show that the yield strength of TiBw/TC4 developed by in situ is 51% higher than that of pure TC4. Compared with CD, the axial force of TiBw/TC4 in UVADis signifi cantly reduced, and the formation of continuous chips and winding cutters is eff ectively reduced. Besides, the wearrate of the cutters is reduced. The number and size of hole wall defects, such as scratches, delamination and tearing, areobviously reduced. As well as the residual stress, white layer thickness and hole wall roughness are reduced by 4.67–16.31%,42.48% and 5.98–29.27% respectively. Within the limits of the experiment, when the spindle speed is 1700 r/min and thefeed speed is 8 mm/min, UVAD can obtain better hole wall surface integrity parameters.

Functional Definition of LuxS, an Autoinducer-2 (AI-2) Synthase and Its Role in Full Virulence of Streptococcus suis Serotype 2

Min Cao,Youjun Feng,Changjun Wang,Feng Zheng,Ming Li,Hui Liao,Yinghua Mao,Xiuzhen Pan,Jing Wang,Dan Hu,Fuquan Hu,Jiaqi Tang 한국미생물학회 2011 The journal of microbiology Vol.49 No.6

Quorum sensing is a widespread chemical communication in response to fluctuation of bacterial population density, and has been implicated into bacterial biofilm formation and regulation of expression of virulence factors. The luxS gene product, S-ribosylhomocysteinase, catalizes the last committed step in biosynthetic pathway of autoinducer 2 (AI-2), a signaling molecule for inter-species quorum sensing. We found a luxS homologue in 05ZYH33, an epidemic strain of Streptococcus suis serotype 2 (SS2) in China. A luxS null mutant (ΔluxS) of 05ZYH33 strain was obtained using an approach of homologous recombination. LuxS was determined to be required for AI-2 production in 05ZYH33 strain of S. suis 2. Inactivation of luxS gene led to a wide range of phenotypic changes including thinner capsular walls, increased tolerance to H_2O_2, reduced adherence capacity to epithelial cells, etc. In particular, loss of LuxS impaired dramatically its full virulence of SS2 in experimental model of piglets, and functional complementation restored it nearly to the level of parent strain. Genome-wide transcriptome analyses suggested that some known virulence factors such as CPS are down-regulated in the ΔluxS mutant, which might in part explain virulence attenuation by luxS deletion. Similarly, 29 of 71 genes with different expression level were proposed to be targets candidate regulated by LuxS/AI-2-dependent quorum sensing.

The Differences of Subcellular Ca²⁺ Distribution in Cucumber Seedling Leaves under NO₃⁻ Stress

Feng Juan Yang,Xiu Feng Wang,Min Wei 한국원예학회 2006 한국원예학회 기타간행물 Vol.- No.-

Identification and Characterization of Bombyx mori LDH Gene through Bioinformatics Approaches

( Min Feng Zhu ),( Ke Ping Chen ),( Qin Yao ) 한국잠사학회 2007 International Journal of Industrial Entomology Vol.15 No.2

Lactate dehydrogenase (LDH) is a ubiquitous enzyme that plays a significant role in the clinical diagnosis of pathologic processes. Discovery of the LDH (BmLDH) gene in B. mori may shed light on its role in the biology of Lepidoptera species, and afford further understanding of the function of the enzyme. In this study, we used the bioinformatics tools to identify LDH gene in B. mori. Sequence analysis showed that BmLDH cDNA contains a 996 bp open reading frame, encoding 331 AA proteins, with seven introns. Compared with hHLDH (human heart LDH), BmLDH contained the same key active sites. Domain search and protein fold recognition analyses provide compelling evidences that the deduced protein is a LDH. Using the computer program MEGA3, we conducted a search for homo-logs of BmLDH among many eukaryotic species and confirmed that the BmLDH was conserved in all organisms investigated. This gene has been registered in GenBank under the accession number EU000385.

Transcriptome profiling of Shindongjin and Sugary mutant at grain-filling stages using RNA-Seq

Feng-Peng Li,Min-Young Yoon,Gang Li,Yong-Jin Park 한국육종학회 2013 한국육종학회 심포지엄 Vol.2013 No.07

Rice (Oryza sativa) is an excellent model monocot with a known genome sequence for studying developmental seeds. In the study, the seeds of 10th day after flowering (DAF) were conducted RNA-Seq of the variety Shindongjin and Sugary mutant using RNA-seq technique. Approximately 202 and 214 million high-quality paired-end reads (101-bp in size) were generated in Shindongjin and Sugary mutant, respectively. Comprehensive analysis on the transcript levels of genes which encode starch-synthesis enzymes is fundamental for the assessment of the function of each enzyme and the regulatory mechanism of starch biosynthesis in seeds. Quantitative real-time PCR was also used to validate the expression profiles of 28 rice genes encoding six classes of enzymes, viz., ADPglucose pyrophosphorylase (AGPase), starch synthase, starch branching enzyme, starch debranching enzyme, starch phosphorylase, and disproportionating enzyme at different developmental grain- filling stages (DAF 1-14) between Shindongjin and Sugary mutant. The results showed that the expression of most of starch synthesis genes were up-regulated except the cytosolic AGPase small subunit2b (AGPS2b), which sharply decreased at grain-filling stages in Sugary mutant. These results will expand our understanding of the complex molecular and cellular events in rice grain-filling stages and provide a fundamental understanding of future studies on developmental endosperm in rice and other cereal crops.