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.

AI 기술을 적용하여 동물 입양을 위한 새로운 서비스 디자인 생성

Guo,Haoyue,Zhang Muxin,Chen Xie,Li Yueyi,Liang Lan,Pan Young Hwan 한국서비스디자인학회 2020 한국서비스디자인학회 학술대회자료집 Vol.2020 No.-

중국 신선식품 플랫폼 신뢰와 이용에 관한 연구

Guo Chen(Chen Guo),류미현(MiHyun Ryu) 한국소비문화학회 2023 소비문화연구 Vol.26 No.1

인터넷 기술과 콜드체인 기술이 끊임없이 개선되면서 신선식품 플랫폼 발전의 토대를 마련했다. 신선식품 플랫폼이 급속하게 발전함에 따라 중국 소비자들이 신선식품을 구매할 수 있는 편리한 채널이 제공되었으며, 이는 신선식품 플랫폼에 대한 소비자들의 이용을 증가시켰다. 따라서 본 연구는 중국소비자를 대상으로 통합기술수용이론 변수, 온라인 리뷰 및 신선식품 관여도가 신선식품 플랫폼의 신뢰에 어떤 영향을 미치는지 알아보고, 플랫폼의 신뢰가 만족도에 미치는 영향과 만족도가 신선식품 플랫폼의 지속적 이용의도에 미치는 영향을 분석하였다. 또한, 소비자 동기의 조절효과를 분석하였다. 연구결과에 따라 성과기대, 촉진조건, 긍정적 리뷰, 부정적 리뷰, 신선식품 관여도는 신뢰에 영향을 미치는 것으로 나타났다. 둘째, 신뢰는 만족도에 영향을 미치며, 만족도는 신선식품 플랫폼의 지속적 이용의도에 영향을 미치는 것으로 나타났다. 셋째, 만족도와 지속적 이용의도 간의 관계에서 유희적 동기의 조절효과가 나타났다. 본 연구는 통합기술수용이론을 적용하고 온라인 리뷰와 신선식품 관여도 변수를 추가하여 신선식품 플랫폼의 지속적 이용의도에 대한 영향요인을 탐색함으로써 이론적 의미와 실무적 가치가 있다. Internet technology and cold chain technology are constantly improving, laying the foundation for the development of a fresh food platform. With the rapid development of the fresh food platform, a convenient channel for Chinese consumers to purchase fresh food has been provided, which has increased consumers’ use of the fresh food platform. Therefore, this study examined the effects of UTAUT variables, online reviews and fresh food involvement on the trust of the fresh food platform and analyzes the impact of platform trust on satisfaction and the impact of satisfaction on the continuous use intention of fresh food platform by targeting Chinese consumers. Also, the moderating effect of consumer motivation was analyzed. According to the research results, performance expectancy, facilitating conditions, positive reviews, negative reviews, and fresh food involvement had a significant impact on trust. Second, we found that trust has an effect on satisfaction, and satisfaction affects on continuous use intention of fresh food platform. Third, the moderating effect of hedonic motivation was found in the relationship between satisfaction and continuous use intention. This paper applies the UTAUT, adding online reviews and fresh food involvement variables to explore the influencing factors of fresh food platform’s continuous use intention, which both have theoretical and practical significance.

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.

Combination of Tumor Volume and Epstein-Barr Virus DNA Improved Prognostic Stratification of Stage II Nasopharyngeal Carcinoma in the Intensity Modulated Radiotherapy Era: A Large-Scale Cohort Study

Qiu-Yan Chen,Shao-Yan Guo,Lin-Quan Tang,Tong-Yu Lu,Bo-Lin Chen,Qi-Yu Zhong,Meng-Sha Zou,Qing-Nan Tang,Wen-Hui Chen,Shan-Shan Guo,Li-Ting Liu,Yang Li,Ling Guo,Hao-Yuan Mo,Rui Sun,Dong-Hua Luo,Chong Zha 대한암학회 2018 Cancer Research and Treatment Vol.50 No.3

Purpose Little is known about combination of the circulating Epstein-Barr viral (EBV) DNA and tumor volume in prognosis of stage II nasopharyngeal carcinoma (NPC) patients in the intensity modulated radiotherapy (IMRT) era. We conducted this cohort study to evaluate the prognostic values of combining these two factors. Materials and Methods By Kaplan-Meier, we compare the differences of survival curves between 385 patients with different EBV DNA or tumor volume levels, or with the combination of two biomarkers mentioned above. Results Gross tumor volume of cervical lymph nodes (GTVnd, p < 0.001) and total tumor volume (GTVtotal, p < 0.001) were both closely related to pretreatment EBV DNA, while gross tumor volume of nasopharynx (GTVnx, p=0.047) was weakly related to EBV DNA. EBV DNA was significantly correlated with progress-free survival (PFS, p=0.005), locoregional-free survival (LRFS, p=0.039), and distant metastasis-free survival (DMFS, p=0.017), while GTVtotal, regardless of GTVnx and GTVnd, had a significant correlation with PFS and LRFS. The p-values of GTVtotal for PFS and LRFS were 0.008 and 0.001, respectively. According to GTVtotal and pretreatment EBV DNA level, patients were divided into a low-risk group (EBV DNA 0 copy/mL, GTVtotal < 30 cm3; EBV DNA 0 copy/mL, GTVtotal  30 cm3; or EBV DNA > 0 copy/mL, GTVtotal < 30 cm3) and a high-risk group (EBV DNA > 0 copy/mL, GTVtotal  30 cm3). When patients in the low-risk group were compared with those in the high-risk group, 3-year PFS (p=0.003), LRFS (p=0.010), and DMFS (p=0.031) rates were statistically significant. Conclusion Pretreatment plasma EBV DNA and tumor volume were both closely correlated with prognosis of stage II NPC patients in the IMRT era. Combination of EBV DNA and tumor volume can refine prognosis and indicate for clinical therapy.

The Prognostic Value of Treatment-Related Lymphopenia in Nasopharyngeal Carcinoma Patients

Li-Ting Liu,Qiu-Yan Chen,Lin-Quan Tang,Shan-Shan Guo,Ling Guo,Hao-Yuan Mo,Ming-Yuan Chen,Chong Zhao,Xiang Guo,Chao-Nan Qian,Mu-Sheng Zeng,Jin-Xin Bei,Jing Tan,Shuai Chen,Ming-Huang Hong,Jian-Yong Shao 대한암학회 2018 Cancer Research and Treatment Vol.50 No.1

Purpose This study was conducted to evaluate the prognostic value of treatment-related lymphopenia in patients with nasopharyngeal carcinoma (NPC). Materials and Methods A total of 413 consecutive stage II-IVb NPC patients treated with concurrent chemoradiotherapy (CCRT) were enrolled. The overall survival (OS), progression-free survival (PFS), and distant metastasis-free survival (DMFS) were calculated with the Kaplan-Meier method, and differences were compared using the log-rank test. Results A minimum (mini)–absolute lymphocyte counts (ALC) of < 390 cells/μL or ALC after 3 months of CCRT (post3m-ALC) < 705 cells/μL was significantly associated with worse outcome than mini-ALC ! 390 cells/μL (OS, p=0.002; PFS, p=0.005; DMFS, p=0.004) or post3m-ALC ! 705 cells/μL (OS, p < 0.001; PFS, p < 0.001; DMFS, p=0.001). Patients with lymphopenia (mini-ALC < 390 cells/μL and post3m-ALC < 705 cells/μL) had a worse prognosis than those without lymphopenia (mini-ALC ! 390 cells/μL and post3m-ALC ! 705 cells/μL) (OS, p < 0.001; PFS, p < 0.001; DMFS, p < 0.001). Multivariate analysis revealed that post3m-ALC was an independent prognostic factor for OS (hazard ratio [HR], 1.76; 95% confidence interval [CI], 1.12 to 2.78; p=0.015), PFS (HR, 1.86; 95% CI, 1.23 to 2.82; p=0.003), and DMFS (HR, 1.87; 95% CI, 1.13 to 3.08; p=0.014). Multivariate analysis also revealed that patients with lymphopenia had a high risk of death (HR, 3.79; 95% CI, 1.75 to 8.19; p=0.001), disease progression (HR, 2.93; 95% CI, 1.59 to 5.41; p=0.001), and distant metastasis (HR, 3.89; 95% CI, 1.67 to 9.10; p=0.002). Multivariate analysis performed with time dependent Cox regression demonstrated ALC was an independent prognostic factor for OS (HR, 0.995; 95% CI, 0.991 to 0.999; p=0.025) and PFS (HR, 0.993; 95% CI, 0.988 to 0.998; p=0.006). Conclusion Treatment-related lymphopenia was a poor prognostic factor in NPC patients.

Grem1 accelerates nucleus pulposus cell apoptosis and intervertebral disc degeneration by inhibiting TGF-β-mediated Smad2/3 phosphorylation

Chen Shunlun,Lei Linchuan,Li Zemin,Chen Fan,Huang Yuming,Jiang Guowei,Guo Xingyu,Zhao Zhuoyang,Liu Hui,Wang Hua,Liu Caijun,Zheng Zhaomin,Wang Jianru 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-

Intervertebral disc degeneration (IVDD) is a main cause of low back pain, and inflammatory factors play key roles in its pathogenesis. Gremlin-1 (Grem1) was reported to induce an inflammatory response in other fields. This study aimed to investigate the mechanisms of Grem1 in the degenerative process of intervertebral discs. Dysregulated genes were determined by analyzing microarray profiles. The expression of Grem1 in 17 human disc samples (male:female = 9:8) and rat models (n = 5 each group) was measured by western blotting (WB), real-time quantitative PCR (RT-qPCR), and immunohistochemistry (IHC). The regulatory effects of Grem1 on apoptosis were examined using siRNAs, flow cytometry, immunofluorescence (IF), and WB. The therapeutic effect was evaluated by locally injecting specific Grem1 siRNA into IVDD rats. The expression of Grem1 was significantly increased in human degenerative intervertebral discs; furthermore, the expression of Grem1 positively correlated with the level of intervertebral disc degeneration. Grem1 was significantly overexpressed in tumor necrosis factor (TNF)-α-induced degenerative NP cells. Apoptosis in degenerative NP cells transfected with siRNA targeting Grem1 was significantly lower than that in the control group. Specific Grem1 siRNA markedly repressed the development of IVDD in surgery-induced IVDD rats. These results indicated that the expression of Grem1 was positively correlated with the severity of intervertebral disc degeneration, and Grem1 siRNA could inhibit Grem1-induced apoptosis and extracellular matrix alterations by mediating the TGF-β/Smad signaling pathway. This study may provide a therapeutic strategy for alleviating inflammation-induced apoptosis associated with intervertebral disc degeneration.

Detoxification, antioxidant, and digestive enzyme activities and gene expression analysis of Lymantria dispar larvae under carvacrol

Chen Yun-ze,Zhang Bo-wen,Yang Jing,Zou Chuan-shan,Li Tao,Zhang Guo-cai,Chen Guang-sheng 한국응용곤충학회 2021 Journal of Asia-Pacific Entomology Vol.24 No.1

Carvacrol is a terpene compound with various biological activities. However, few studies have specifically focused on its insecticidal activity and mechanism of carvacrol. The larvae of Lymantria dispar are seriously harmful herbivorous insect. This study measured the antifeedant, growth-inhibitory, and toxic effects of carvacrol on L. dispar larvae. To further clarify the insecticidal mechanism of carvacrol, the effects of carvacrol on detoxifying enzymes, antioxidative enzymes, digestive enzyme activities, and the mRNA expression of the abovementioned enzyme genes were investigated. The results of the study showed that the median lethal concentration (LC 50 ) and the sublethal concentration (LC 20 ) of carvacrol were 1.120 mg/mL and 0.297 mg/mL, respectively, at 72 h. After LC 20 treatment of L. dispar larvae for 72 h, food intake and weight gain were significantly lower compared with the control. Enzyme activity assays showed that carvacrol significantly inhibited the activities of carboxylesterase (CarE), glutathione S-transferase (GST), and acetylcholinesterase (AchE), and the inhibition rate of AchE activity was highest (66.51%). Carvacrol also activated the activities of superoxide dismutase (SOD) and catalase (CAT), while it inhibited the activities of lipase (LIP) and amylase (AMS), and first inhibited and then activated protease. In addition, qRT-PCR tests showed that carvacrol affected the mRNA expression levels of CarE, GST, AchE, SOD, CAT, LIP, AMS, and protease. This study helps to clarify the insecticidal mechanism of carvacrol on L. dispar larvae.

Hybrid PWM Modulation Technology Applied to Three-Level Topology-Based PMSMs

Chen, Yuanxi,Guo, Xinhua,Xue, Jiangyu,Chen, Yifeng The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.1

The inverter is an essential part of permanent magnet synchronous motor (PMSM) drive systems. The performance of an inverter is greatly influenced by its modulation strategy. Using a proper management of modulation strategies can guarantee high performance from a PMSM under various speed conditions. Switching between modulations is a pivotal technique that determines the performance of a PMSM. Most works on hybrid methods focus on two-level induction motors drive systems. In this paper, in order to improve the performance of PMSMs under various speed conditions, a hybrid method of a pulse width modulation (PWM) control scheme based on a neutral-point-clamped (NPC) three level topology was proposed. This hybrid PWM modulation comprised space vector PWM (SVPWM) and selective harmonic elimination PWM (SHEPWM). Under low speed conditions, the SVPWM is employed to cause the PMSM to start smoothly, and to obtain a rapid response from the control system. Under high speed conditions, the SHEPWM is employed to reduce the switching frequency and to eliminate particular current harmonics. Moreover, the harmonic characteristics of different modulations are analyzed to obtain a smooth transition between the SHEPWM and the SVPWM. Experimental and simulation results indicated the effectiveness of the proposed control method.

Dose-Dependent Associations between Wine Drinking and Breast Cancer Risk - Meta-Analysis Findings

Chen, Jia-Yan,Zhu, Hong-Cheng,Guo, Qing,Shu, Zheng,Bao, Xu-Hui,Sun, Feng,Qin, Qin,Yang, Xi,Zhang, Chi,Cheng, Hong-Yan,Sun, Xin-Chen Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.3

Purpose: To investigate any potential association between wine and breast cancer risk. Materials and Methods: We quantitatively assessed associations by conducting a meta-analysis based on evidence from observational studies. In May 2014, we performed electronic searches in PubMed, EmBase and the Cochrane Library to identify studies examining the effect of wine drinking on breast cancer incidence. The relative risk (RR) or odds ratio (OR) were used to measure any such association. Results: The analysis was further stratified by confounding factors that could influence the results. A total of twenty-six studies (eight case-control and eighteen cohort studies) involving 21,149 cases were included in our meta-analysis. Our study demonstrated that wine drinking was associated with breast cancer risk. A 36% increase in breast cancer risk was observed across overall studies based on the highest versus lowest model, with a combined RR of 1.0059 (95%CI 0.97-1.05) in dose-response analysis. However, 5 g/d ethanol from wine seemed to have protective value from our non-linear model. Conclusions: Our findings indicate that wine drinking is associated with breast cancer risk in a dose-dependent manner. High consumption of wine contributes to breast cancer risk with protection exerted by low doses. Further investigations are needed for clarification.