목질계 바이오매스를 이온성 용매로 전처리하여 수소 생산 향상

DONG DANDAN(Dandan Dong),이재우(Jae Woo Lee),신동혁(Donghyuk Shin),정현정(Hyeon Jeong Jeong),임해찬(Hae Chan Lim) 대한환경공학회 2021 대한환경공학회 학술발표논문집 Vol.2021 No.11

Service Quality Gap Model for Analysis and Improvement of Plastic Surgery Customer Satisfaction in South Korea

Dandan Yu,Lanmeng Wu,LIUZIYANG 한국무역통상학회 2020 무역통상학회지 Vol.20 No.5

The purpose of this study is to examine the experiences of customers who go to Korea to undergo plastic surgery. This study applies the quality-of-service gap model to understand and analyze customer satisfaction and service demand and to know various measures and suggestions to improve medical services. A questionnaire survey is adopted according to the basic theory of the service quality gap model. Based on actual conditions of hospital work in Korea, the gap model of medical service quality is established. SPSS22.0 statistical package was used to analyze and process data. Results show that plastic surgery customers’ perception of medical services is higher than expected. At the same time, plastic surgery customers indicate the highest evaluation of the quality of medical services. These customers have the highest expectation of assurance in medical service quality and the lowest expectation on empathy. Among the plastic surgery clients in various age groups, the younger ones exhibit greater difference between the expected value and actual perceived value in terms of the reliability of medical service quality. Therefore, we can conclude that the service quality gap model is feasible in analyzing and improving the satisfaction of hospital patients. This model is a reliable theoretical reference that hospital administrators can use to address issues related to medical service quality.

Likelihood-based tests on moderate-high-dimensional mean vectors with unequal covariance matrices

Dandan Jiang 한국통계학회 2017 Journal of the Korean Statistical Society Vol.46 No.3

This paper considers linear hypotheses of a set of high-dimensional mean vectors with unequal covariance matrices. To test the hypothesis H0 : qi =1 βiμi = μ0, we use the CLT for the linear spectral statistics of a high-dimensional F-matrix in Zheng (2012) to establish a test statistic based on the likelihood ratio test statistic that is applicable to high-dimensional non-Gaussian variables in a wide range. Furthermore, the results of a simulation are provided to compare the proposed test with other high-dimensional tests. As shown by the simulation results, the empirical size of our proposed test is closer to a significance level, whereas our empirical powers dominate those of the other tests due to the likelihood-based statistic.

Secure Beamforming with Artificial Noise for Two-way Relay Networks

( Dandan Li ),( Ke Xiong ),( Guanyao Du ),( Zhengding Qiu ) 한국인터넷정보학회 2013 KSII Transactions on Internet and Information Syst Vol.7 No.6

This paper studies the problem of secure information exchange between two sources via multiple relays in the presence of an eavesdropper. To this end, we propose a relay beamforming scheme, i.e., relay beamforming with artificial noise (RBwA), where the relay beamforming vector and the artificial noise vector are jointly designed to maintain the received signal-to-interference-ratio (SINR) at the two sources over a predefined Quality of Service (QoS) threshold while limiting the received SINR at the eavesdropper under a predefined secure threshold. For comparsion, the relay beamforming without artificial noise (RBoA) is also considered. We formulate two optimization problems for the two schemes, where our goal is to seek the optimal beamforming vector to minimize the total power consumed by relay nodes such that the secrecy of the information exchange between the two sources can be protected. Since both optimization problems are nonconvex, we solve them by semidefinite program (SDP) relaxation theory. Simulation results show that, via beamforming design, physical layer secrecy of two-way relay networks can be greatly improved and our proposed RBwA outperforms the RBoA in terms of both low power consumption and low infeasibility rate.

TEOA, a triterpenoid from Actinidia eriantha, induces autophagy in SW620 cells via endoplasmic reticulum stress and ROS-dependent mitophagy

Dandan Zhang,Cuixia Gao,Ruyi Li,Lin Zhang,Jingkui Tian 대한약학회 2017 Archives of Pharmacal Research Vol.40 No.5

2a,3a,24-Thrihydroxyurs-12-en-28-oicacid (TEOA),a pentacyclic triterpenoid, isolated from the roots of Actinidiaeriantha, exhibits significant cytotoxicity against SW620, BGC-823, HepG-2, A549 and PC-3 cancer cells. In this study, weinvestigated the underlying molecular mechanism of the anticanceractivity of TEOA in SW620 cells.We demonstrated thatTEOA induced apoptosis through cleavage of caspase-9 andPARP in SW620 cells. In addition, evidence of TEOA-mediatedautophagy included the induction of autophagolysosomesand activation of autophagic markers LC-3B and p62. Furtheranalysis illustrated that TEOA promoted the phosphorylation ofPERK and elF2a, followed by up-regulation of the downstreamprotein CHOP, suggesting the involvement of PERK/eIF2a/CHOP pathway and ER stress in TEOA-induced autophagy inSW620 cells. Meanwhile, TEOA-mediated PINK1, Parkin,ubiquitin and p62 activation revealed that TEOA inducedspecific autophagy-mitophagy in SW620 cells. Additionally, anantioxidant NAC attenuated the TEOA-induced mitophagy,indicating that TEOA triggers mitophagy via a ROS-dependentpathway. Collectively, our findings revealed a novel cellularmechanism of TEOA in the colon cancer cell line SW620, thusproviding a molecular basis for developing TEOA into an antitumorcandidate.

Fashionable styles and information sources: an exploratory study of Hangzhou, China

Dandan Chen,하지수 한국의류학회 2016 Fashion and Textiles Vol.3 No.1

The exploratory study aims to examine Hangzhou fashion in the context of globalization and localization through in-depth interviews. Sixteen young females from Hangzhou were interviewed. In the 1990s young females from Hangzhou had a weak concept of fashionable style and they just had a preference for the feminine style, which is derived from a regional culture. In the 2010s, young females’ concept regarding fashion have changed from fashionable (时髦) to stylish (有型), leading to a variety of fashionable styles. The popular Korean, European and minimalist styles mostly originate from foreign dramas and fashion advertisements from the Internet. This qualitative research verified that there was a diminishing sense of locality and cultural identity in young females’ fashion in Hangzhou. However, the impact of globalcultural eclecticism and mass media imagery appears larger for young females’ fashion in the city, especially through the Internet, especially in the spread of SNS, online shopping malls, and online video sites. Therefore, fashion brands should expand the brand culture influence through online media. Presently, the mobile apps in Hangzhou such as Wechat and Instagram may be the most helpful tool for brand culture spreading.

Downregulation of FoxM1 sensitizes nasopharyngeal carcinoma cells to cisplatin via inhibition of MRN-ATM-mediated DNA repair

( Dandan Li ),( Lin Ye ),( Yue Lei ),( Jie Wan ),( Hongyan Chen ) 생화학분자생물학회(구 한국생화학분자생물학회) 2019 BMB Reports Vol.52 No.3

Chemoresistance is the primary obstacle in the treatment of locally advanced and metastatic nasopharyngeal carcinoma (NPC). Recent evidence suggests that the transcription factor forkhead box M1 (FoxM1) is involved in chemoresistance. Our group previously confirmed that FoxM1 is overexpressed in NPC. In this study, we investigated the role of FoxM1 in cisplatin resistance of the cell lines 5-8F and HONE-1 and explored its possible mechanism. Our results showed that FoxM1 and NBS1 were both overexpressed in NPC tissues based on data from the GSE cohort (GSE12452). Then, we measured FoxM1 levels in NPC cells and found FoxM1 was overexpressed in NPC cell lines and could be stimulated by cisplatin. MTT and clonogenic assays, flow cytometry, γH2AX immunofluorescence, qRT-PCR, and western blotting revealed that downregulation of FoxM1 sensitized NPC cells to cisplatin and reduced the repair of cisplatin-induced DNA double-strand breaks via inhibition of the MRN (MRE11-RAD50-NBS1)-ATM axis, which might be related to the ability of FoxM1 to regulate NBS1. Subsequently, we demonstrated that enhanced sensitivity of FoxM1 knockdown cells could be reduced by overexpression of NBS1. Taken together, our data demonstrate that downregulation of FoxM1 could improve the sensitivity of NPC cells to cisplatin through inhibition of MRN-ATM-mediated DNA repair, which could be related to FoxM1-dependent regulation of NBS1. [BMB Reports 2019; 52(3): 208-213]

An S-scheme photocatalyst constructed by modifying Ni-doped Sn3O4 micro-flowers on g-C3N4 nanosheets for enhanced visible-light-driven hydrogen evolution

Dandan Wang,Zhaoxin Lin,Chun Miao,Wei Jiang,Hongji Li,Chunbo Liu,Guangbo Che 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.113 No.-

Carbon nitrides (g-C3N4) is considered to be the prospective semiconductor photocatalyst for photocatalytic H2 evolution. Nevertheless, it suffers from low charge transfer efficiency and fewer metal active sites. Thereby, Ni-Sn3O4/g-C3N4 photocatalysts were constructed by anchoring Ni-doped Sn3O4 micro-flowers on g-C3N4 via a feasible and straightforward solvothermal treatment. The prepared Ni-Sn3O4/g-C3N4 S-scheme heterojunction could improve the transfer and separation efficiency of photo-generated electron-hole pairs by facilitating the electrons transfer from Ni-Sn3O4 to g-C3N4. Moreover, the photocatalytic H2 production performance was ameliorated due to the established internal electric field and the energy band bending in Ni-Sn3O4/g-C3N4 S-scheme heterojunction. Meanwhile, the doping Ni in Sn3O4 exposed more active sites in Ni-Sn3O4/g-C3N4 heterojunction for producing H2. As a result, Ni-Sn3O4/g-C3N4-5 photocatalyst exhibited outstanding H2 yields of 1961 µmol h−1 g−1 under visible light irradiation in comparison with pure Ni-Sn3O4 (12 µmol h−1 g−1) and bared g-C3N4 (1391 µmol h−1 g−1). Furthermore, the S-scheme mechanism in Ni-Sn3O4/g-C3N4 heterojunction for producing H2 by oxidizing H2O was proposed. This study provides helpful guide for developing efficient g-C3N4-based photocatalytic systems.

Some Geometric Constants Related to the Heights and Mid lines of Triangles in Banach Space

Dandan Du,Yuankang Fu,Zhijian Yang,Yongjin Li 경북대학교 자연과학대학 수학과 2023 Kyungpook mathematical journal Vol.63 No.1

In this paper, we introduce two new geometric constants related to the heights of triangles: ∆H(X) and ∆h(X, I). We also propose two new geometric constants, ∆m(X) and ∆M(X), related to the midlines of equilateral triangles, and discuss the relation between the heights and midlines in equilateral triangles. We give estimates for these geometric constants in terms of other geometric parameters, and the geometric constants are used to discuss geometric properties such as uniform non-squareness, uniform normal structure, and the fixed point property.

Evaluation of Water Environment Performance Based on a DPSIR-SBM-Tobit Model

Dandan Zhang,Juqin Shen,Fu-hua Sun 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.5

Environmental problems – specifically relating to water – have become the key factors restricting sustainable development. To evaluate the performance of water environment, this study takes 31 provinces in China as the research area and constructs a water environment performance evaluation index system based on a DPSIR framework (Drivers, Pressures, State, Impact and Response). The undesirable output slack measure model (SBM) is used to calculate the water environment performance of 31 provinces from 2005 to 2017. According to the study, the performance of the water environment in China shows a trend of decline, and the overall performance is low. The water environment performance in different provinces shows obvious differences. The Tobit model is then introduced to analyze the influence of indicators on water environment efficiency. The driving force indicators have significant negative effects on water environment performance. The pressure indicators have significant positive effects on the water environment performance. The state indicators play a significant role in promoting the improvement of water environment performance. With regard to the impact indicators, both industrial added value water consumption and GDP growth rate have significant negative effects on water environment performance. The impact of different response measures on water environment performance is inconsistent.