Synthesis of Noble Metal (Au, Ag)@TiO2 Core-shell Nanoparticles and Their Photocatalytic Properties (초)

( Wu Xiao Feng ),( Jeong Mo Yoon ),( Yeon Tae Yu ) 대한금속재료학회 ( 구 대한금속학회 ) 2008 대한금속재료학회 학술대회 개요집 Vol.2008 No.1

Synthesis of Core−Shell Au@TiO₂ Nanoparticles with Truncated Wedge-Shaped Morphology and Their Photocatalytic Properties

Wu, Xiao-Feng,Song, Hai-Yan,Yoon, Jeong-Mo,Yu, Yeon-Tae,Chen, Yun-Fa American Chemical Society 2009 Langmuir Vol.25 No.11

<P>Core−shell Au@TiO<SUB>2</SUB> nanoparticles with truncated wedge-shaped TiO<SUB>2</SUB> morphology have been synthesized successfully by a simple and flexible hydrothermal route. Morphological evolution of TiO<SUB>2</SUB> shells was investigated by transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and X-ray diffraction technique. It has been revealed that the truncated wedge-shaped TiO<SUB>2</SUB> shells experience an epitaxially segmented orientation growth. Also, the (101) crystal planes of TiO<SUB>2</SUB> crystals grow preferentially on the surface of gold nanocrystals stabilizing the heterointerfaces, then faster [001] growth results in the “budding” process occurs, producing growth sites on the initial deposition TiO<SUB>2</SUB> layers, where the TiO<SUB>2</SUB> crystals grow up into truncated wedge-shaped morphologies. It is also found that morphological evolution of TiO<SUB>2</SUB> shells is dependent on the produced F<SUP>−</SUP> ion concentration from hydrolyzed TiF<SUB>4</SUB> precursors. The produced F<SUP>−</SUP> ions not only facilitate the formation of well-defined wedge-like TiO<SUB>2</SUB> shells, but also contribute to the externally exposed truncated crystal {004} facets. As the representative photocatalyst, the catalytic activities of the resultant core−shell Au@TiO<SUB>2</SUB> nanoparticles were investigated by photoinitiated oxidation degradation of gaseous acetaldehyde. It has been indicated that the nanostructured core−shell Au@TiO<SUB>2</SUB> photocatalyst represents high photocatalytic activity when exposed to UV or visible light irradiation. The high phototocatalytic performance is also largely attributed to the preferentially grown TiO<SUB>2</SUB> shell structures and metal (Au)-TiO<SUB>2</SUB> heterointerfaces.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/langd5/2009/langd5.2009.25.issue-11/la900035a/production/images/medium/la-2009-00035a_0005.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/la900035a'>ACS Electronic Supporting Info</A></P>

Salivary Pepsin as an Intrinsic Marker for Diagnosis of Sub-types of Gastroesophageal Reflux Disease and Gastroesophageal Reflux Disease-related Disorders

( Yan-jun Wang ),( Xiu-qiong Lang ),( Dan Wu ),( Yu-qin He ),( Chun-hui Lan ),( Xiao-xiao ),( Bin Wang ),( Duo-wu Zou ),( Ji-min Wu ),( Yong-bin Zhao ),( Peter W Dettmar ),( Dong-feng Chen ),( Min Yan 대한소화기 기능성질환·운동학회 2020 Journal of Neurogastroenterology and Motility (JNM Vol.26 No.1

Background/Aims To determine the value of salivary pepsin in discriminating sub-types of gastroesophageal reflux disease (GERD) and GERD-related disorders. Methods Overall, 322 patients with different sub-types of GERD and 45 healthy controls (HC) were studied. All patients took Gastroesophageal Reflux Disease Questionnaire (GerdQ) and underwent endoscopy and 24-hour esophageal pH monitoring and manometry. Salivary pepsin concentration (SPC) was detected by using colloidal gold double-antibody immunological sandwich assay. Oral esomeprazole treatment was administrated in the patients with non-erosive reflux disease (NERD) and extra-esophageal symptoms (EES). Results Compared to HC, patients with erosive esophagitis, NERD, EES, EES plus typical GERD symptoms, or Barrett’s esophagus had a higher prevalence of saliva and SPC (all P < 0.001). There was no significant difference in the positive rate for pepsin in patients with functional heartburn or GERD with anxiety and depression, compared to HC. After esomeprazole treatment, the positive rate and SPC were significantly reduced in NERD (both P < 0.001) and in EES (P = 0.001 and P = 0.002, respectively). Of the 64 NERD patients, 71.9% (n = 46) were positive for salivary pepsin, which was significantly higher than the rate (43.8%, n = 28) of pathological acid reflux as detected by 24-hour esophageal pH monitoring (P = 0.002). Conclusions Salivary pepsin has an important significance for the diagnosis of GERD and GERD-related disorders. Salivary pepsin and 24-hour esophageal pH monitoring may complement with each other to improve the diagnostic efficiency.

Comparative transcriptomic screen identifies expression of key genes involved in pattern-triggered immunity induced by salicylic acid in strawberry

Feng Jun,Wu Xiao-Ying,Xiu Yu,Zheng Cai-Xia 한국원예학회 2023 Horticulture, Environment, and Biotechnology Vol.64 No.5

The destructive illness powdery mildew, caused by Podosphaera aphanis , reduces strawberry yield. However, the mechanism through which exogenous salicylic acid can enhance resistance to P. aphanis remains unknown. Therefore, this study aimed to investigate the underlying mechanism of SA-induced resistance in strawberry leaves against P. aphanis using a comparative RNA-seq approach. Upon observing the symptoms, it was found that SA partially contributed to strawberry resistance against P. aphanis by increasing H 2 O 2 levels during the initial stages. To mitigate the eff ects of H 2 O 2 , SA-treated leaves signifi cantly boosted the activities of enzymes such as superoxide dismutases (SOD), catalases (CAT), and peroxidases (POD). RNA profi ling identifi ed several diff erentially expressed genes (DEGs) associated with the reactive oxygen species (ROS)-redox pathway. Moreover, SA-induced leaves fortifi ed the cell wall to prevent P. aphanis penetration. Using weighted gene coexpression network analysis (WGCNA), three modules (red, green, and yellow) were constructed, showing a strong correlation with enhanced resistance. Predictably, cyclic nucleotide-gated channels (CNGC) were identifi ed as potential players in Ca 2+ signaling linked to the PTI response. Additionally, the presence of WRKY33 and defense-related genes such as PR10 were associated with enhanced resistance. It is plausible that strawberries exposed to SA trigger ROS and Ca 2+ signaling, along with signifi cantly elevated WRKY33 expression, to facilitate the production of PR10 and camalexin, which help protect against P. aphanis .

Genetic characterization of bovine viral diarrhea virus strains in Beijing, China and innate immune responses of peripheral blood mononuclear cells in persistently infected dairy cattle

Xiao Gang Weng,Quan Jiang Song,Qiong Wu,Ming Chao Liu,Meng Ling Wang,Jiu Feng Wang 대한수의학회 2015 Journal of Veterinary Science Vol.16 No.4

To acquire epidemiological data on the bovine viral diarrhea virus (BVDV) and identify cattle persistently infected (PI) with this virus, 4,327 samples from Holstein dairy cows were screened over a four-year period in Beijing, China. Eighteen BVD viruses were isolated, 12 from PI cattle. Based on genetic analysis of their 5’-untranslated region (5’-UTR), the 18 isolates were assigned to subgenotype BVDV-1m, 1a, 1d, 1q, and 1b. To investigate the innate immune responses in the peripheral-blood mononuclear cells of PI cattle, the expression of Toll-like receptors (TLRs), RIG-I-like receptors, interferon-a (IFN-a), IFN-b, myxovirus (influenza virus) resistance 1 (MX1), and interferon stimulatory gene 15 (ISG15) was assessed by qPCR. When compared with healthy cattle, the expression of TLR-7, IFN-a, and IFN-b mRNA was downregulated, but the expression of MX1 and ISG-15 mRNA was upregulated in PI cattle. Immunoblotting analysis revealed that the expression of interferon regulatory factor 3 (IRF-3) and IRF-7 was lower in PI cattle than in healthy cattle. Thus, BVDV-1m and 1a are the predominant subgenotypes in the Beijing region, and the strains are highly divergent. Our findings also suggest that the TLR-7/IRF-7 signaling pathway plays a role in evasion of host restriction by BVDV.

Genome-wide identification of polyphenol oxidase (PPO) family members in eggplant (Solanum melongena L.) and their expression in response to low temperature

Xiao Kai,Liu Xiaohui,Zhang Aidong,Zha Dingshi,Zhu WeiMin,Tan Feng,Huang Qianru,Zhou Yaru,Zhang Min,Li Jianyong,Wu Xuexia 한국원예학회 2022 Horticulture, Environment, and Biotechnology Vol.63 No.5

Browning of fresh-cut eggplant (Solanum melongena L.) reduces its sensory and nutritional qualities and further influences consumption. Polyphenolic oxidases (PPOs) are key enzymes involved in browning, but the mechanisms that regulate the expression of PPO genes are still unclear. Here, 12 SmPPO genes were identified and phylogenetic analysis clustered these genes into four branches. Protein and cis-regulatory element analyses showed that the SmPPO gene family has a conserved gene structure and diverse functions. Gene expression analysis in different tissues showed that the expression of SmPPO2, SmPPO3, SmPPO6, SmPPO7, and SmPPO10 was higher in the flesh of the browning-sensitive inbred line ‘36’ than in the flesh of the browning-resistant line ‘Fu’. Furthermore, almost all SmPPO genes in ‘36’ were upregulated at 4 °C and 36 °C compared with those in ‘Fu’, and the expression increased earlier after harvest. In addition, SmPPO1, SmPPO6, SmPPO7, and SmPPO10 expression was significantly elevated in ‘36’ after 2 days at 36 °C. These results suggest that SmPPOs are key modulators of eggplant browning and provide candidate genes for further research on the mechanisms regulating fruit browning.

New Rotor Topologies for Electromagnetic Forces and Acoustic Noise Reduction of claw Pole Alternators

Wu Shuanglong,Yan Xiangyu,Chen Zhaoguo,Zhang Yaodan,Feng Xiao 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.5

This paper proposes a new rotor topology to reduce the electromagnetic forces and acoustic noise of automotive claw pole alternators. A noise bench test was first conducted for a 12-pole/36-slot claw pole alternator and the characteristics of the noise were analyzed. The analytical expression of electromagnetic forces was then derived, and the noise generation mechanism was illustrated theoretically. According to the distribution of the electromagnetic forces on the stator surface, a new rotor structure with rotor claw poles offset was proposed to decrease the force harmonics. Simulation results showed that when the rotor claws of N pole and S pole were offset in the same direction which was consistent with the direction of rotor rotation, the electromagnetic noise would be reduced by 6.7 dB(A), without sacrificing the output current. However, when the rotor claws were offset in the opposite direction, the electromagnetic noise could not be effectively reduced and was even slightly increased. The topology proposed in this paper provides an effective solution for the design and optimization of electromagnetic noise in claw pole alternators.

Failure analysis of prestressed concrete containment vessels under internal pressure considering thermomechanical coupling

Wu Yu-Xiao,Fei Zi-Jian,Feng De-Cheng,Song Meng-Yan 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.12

After a loss of coolant accident (LOCA) in the prestressed concrete containment vessels (PCCVs) of nuclear power plants, the coupling of temperature and pressure can significantly affect the mechanical properties of the PCCVs. However, there is no consensus on how this coupling affects the failure mechanism of PCCVs. In this paper, a simplified finite element modeling method is proposed to study the effect of temperature and pressure coupling on PCCVs. The experiment results of a 1:4 scale PCCV model tested at Sandia National Laboratory (SNL) are compared with the results obtained from the proposed modeling approach. Seven working conditions are set up by varying the internal and external temperatures to investigate the failure mechanism of the PCCV model under the coupling effect of temperature and pressure. The results of this paper demonstrate that the finite element model established by the simplified finite element method proposed in this paper is highly consistent with the experimental results. Furthermore, the stress-displacement curve of the PCCV during loading can be divided into four stages, each of which corresponds to the damage to the concrete, steel liner, steel rebar, and prestressing tendon. Finally, the failure mechanism of the PCCV is significantly affected by temperature.

Application of Organic Solvent System for Lipase-catalyzed Regioselective Benzoylation of 1-β-D-arabinofuranosylcytosine

Xiao-Feng Li,Min-Hua Zong,Guang-Lei Zhao,Yi-Gang Yu,Hui Wu 한국생물공학회 2010 Biotechnology and Bioprocess Engineering Vol.15 No.4

In this paper, enzymatic regioselective acylation of 1-β-D-arabinofuranosylcytosine (ara-C) with vinyl benzoate (VB) using immobilized Candida antarctica lipase B in binary organic solvents was explored. It was found that the lipase showed high regioselectivity (> 99%) towards the 5'-OH of ara-C in the representative organic solvent mixture (hexane-pyridine). To understand the enzymatic processes and provide a fair comparison of hexane-pyridine with C4MIm·PF6-pyridine (the representative ionic liquid-containing system), the effect of each process variable on the reactions in hexane-pyridine was investigated. The results indicate that the optimum hexane content,initial a w, molar ratio of VB to ara-C, and temperature were 28% (v/v), 0.11, 15, and 40°C, respectively. Under optimized conditions, the initial reaction rate in hexanepyridine (44.4 mM/h) was much higher than that in C4MIm·PF6-pyridine (29.4 mM/h) for each case. The maximum conversion yield, however, was increased when the reaction system was shifted from hexane-pyridine to C4MIm·PF6-pyridine. Further study revealed that the presence of an acidic by-product (benzoate acid, released during the acylation process) may cause rapid inactivation of the enzyme in hexane-pyridine, leading to a lower conversion rate, whereas the ionic liquid may have coating and protecting effects on the lipase during the reaction.

β-arrestin Promotes c-Jun N-terminal Kinase Mediated Apoptosis via a GABA_BR·β-arrestin·JNK Signaling Module

Wu, Jin-Xia,Shan, Feng-Xiao,Zheng, Jun-Nian,Pei, Dong-Sheng Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.2

Evidence is growing that the $GABA_B$ receptor, which belongs to the G protein-coupled receptor (GPCR) superfamily, is involved in tumorigenesis. Recent studies have shown that ${\beta}$-arrestin can serve as a scaffold to recruit signaling protein c-Jun N-terminal knase (JNK) to GPCR. Here we investigated whether ${\beta}$-arrestin recruits JNK to the $GABA_B$ receptor and facilitates its activation to affect the growth of cancer cells. Our results showed that ${\beta}$-arrestin expression is decreased in breast cancer cells in comparison with controls. ${\beta}$-arrestin could enhance interactions of the $GABA_BR{\cdot}{\beta}-arrestin{\cdot}JNK$ signaling module in MCF-7 and T-47D cells. Further studies revealed that increased expression of ${\beta}$-arrestin enhances the phosphorylation of JNK and induces cancer cells apoptosis. Collectively, these results indicate that ${\beta}$-arrestin promotes JNK mediated apoptosis via a $GABA_BR{\cdot}{\beta}-arrestin{\cdot}JNK$ signaling module.