Synthesis and Properties of Optically Active Helical Polyethers Bearing Indole or Carbazole Derivatives

Chunhui Zhao,Kunbing Ouyang,Nian-Fa Yang,Jin Zhang,Zhu Sheng Yang 한국고분자학회 2016 Macromolecular Research Vol.24 No.5

Six optically active oxide propane monomers (1m-6m) were synthesized in a very facile way. The monomers were polymerized using potassium hydroxide (KOH) as an initiator to afford the corresponding polyethers (1p-6p). The polyether (R)-1p (specific rotation, [α]=+331) exhibited optical rotation as large as fourfold that of the monomer (R)-1m ([α]=-10). The specific optical rotation, circular dichroism (CD) and ultraviolet (UV)-visible spectra data showed that the obtained polymers can keep a prevailing helicity of the backbone in solution.

Clinical and Genetic Features of Brainstem Glioma in Adults: A Report of 50 Cases in a Single Center

Chunhui Zhou,Hao Zhao,Fan Yang,Luokai Huangfu,Chao Dong,Shuwei Wang,Jianning Zhang 대한신경과학회 2021 Journal of Clinical Neurology Vol.17 No.2

Background and Purpose Brainstem gliomas (BSGs) in adults are rare brain tumors with dismal outcomes. The aim of this study was to determine the clinical and genetic features in a series of BSGs and their association with the prognosis. Methods Fifty patients who underwent a stereotactic biopsy between January 2016 and April 2018 at a single institution were collected. Data on clinicopathological characteristics were analyzed and factors associated with patient survival were identified using a Cox regression model. Results The median age at diagnosis was 55.5 years, and 62% of the patients were male. Glioblastoma (44%) accounted for the largest proportion of BSGs, and oligodendroglioma (2 of 50) was rarely encountered. The IDH mutation (6 of 44) occurred infrequently in astrocytomas, and IDH-mutant tumors harbored both ATRX loss and MGMT promoter methylation at a relatively low level. Wild-type IDH astrocytomas were identified as having high rates of 1p/19q codeletion (5 of 38) and loss of heterozygosity 1p (8 of 38) or 19q (8 of 38) only. In diffuse midline glioma H3K27M mutant, MGMT promoter methylation occurred in three of four cases. Patients were offered radiotherapy and/or concurrent/adjuvant temozolomide chemotherapy, and their median survival time was 13 months. Multivariate analysis revealed that a low tumor grade, absence of tumor enhancement, duration of symptoms ≥3 months, Karnofsky performance status ≥70, and ATRX loss conferred a survival advantage. Conclusions Adult BSGs showed different molecular genetic characteristics, but also resembled supratentorial gliomas in their clinical features associated with oncological outcomes.

Bimetallic PtRu Nanoparticles Supported on Functionalized Multiwall Carbon Nanotubes as High Performance Electrocatalyst for Direct Methanol Fuel Cells

Chunhui Tan,Juhui Sa,Feipeng Cai,Bo Jiang,Gai Yang,Bo Wang,Jinhua Gao,Hua Chen,Xianzhong Qin 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.2

PtRu nanoparticles (NPs) supported on acid treated multiwall carbon nanotubes (Pt1Ru1/ MWCNTs) were prepared by a modified polyol method without adding any other surfactant or protective agent. The structural and compositional properties of the as-obtained samples were characterized by transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD) and X-ray photoelectron (XPS) spectroscopy. The electrocatalytic performance of the catalyst was evaluated by cyclic voltammetry (CV), CO stripping voltammetry and chronoamperometry, indicating a high catalytic activity, excellent CO tolerance and stability for methanol oxidation. Interestingly, a series of accurate controllable experiments have been designed to explore the enhancement mechanism of Pt1Ru1/MWCNTs for methanol oxidation reaction. Most importantly, Pt1Ru1/MWCNTs composites were used as an anode catalyst in the direct methanol fuel cells (DMFCs) exhibiting outstanding power density (126.1 mW/cm2) 1.7 times higher than that of the commercial catalyst of Pt1Ru1/C (74.1 mW/cm2Þ)(E-TEK).

Synthesis of CdxZn1-xS@MIL-101(Cr) Composite Catalysts for the Photodegradation of Methylene Blue

Shipeng Yang,Siwei Peng,Chunhui Zhang,Xuwen He,Yaqi Cai 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.10

Nanoparticles of the semiconductor catalyst CdxZn1-xS were embedded into the metal organic framework MIL-101(Cr) to obtain CdxZn1-xS@MIL-101(Cr) nanocomposites. These materials not only possess high surface areas and mesopores but also show good utilization of light energy. The ultraviolet-visible diffuse reflectance patterns of CdxZn1-xS@MIL-101(Cr) nanocomposites showed that Cd0.8Zn0.2S@MIL-101(Cr) possessed good visible light response ability among the synthesized nanocomposites. The photocatalytic performance of the CdxZn1-xS@MIL-101(Cr) nanocomposites were tested via degradation and mineralization of methylene blue in neutral water solution under light irradiation using a 300W xenon lamp. As a result, using Cd0.8Zn0.2S@MIL-101(Cr) as a catalyst, 99.2% of methylene blue was mineralized within 30 min. Due to the synergistic effect of adsorption by the MIL-101(Cr) component and photocatalytic degradation provided by the Cd0.8Zn0.2S component, the Cd0.8Zn0.2S@MIL-101(Cr) catalyst displayed superior photocatalytic performance relative to Cd0.8Zn0.2S and MIL-101(Cr). Furthermore, Cd0.8Zn0.2S@MIL-101(Cr) possessed excellent stability during photo-degradation and exhibited good reusability. The remarkable photocatalytic performance of Cd0.8Zn0.2S@MIL-101(Cr) is likely due to the effective transfer of electrons and holes at the heterojunction interfaces.

Enhancing the adsorption function of F⁻ by iron and zirconium doped zeolite: Characterization and parameter optimization

Bo Yang,Chaomin Jia,Guirong Sun,Bingxu Quan,Chunhui Zhang,Qianqian Huo,Peidong Su 대한환경공학회 2023 Environmental Engineering Research Vol.28 No.2

This study presented an original study on the F⁻ removal by Fe and Zr doped Gismondine-dominated Zeolite. Various modified zeolites are prepared by systematically adjusting the synthesis variables, namely pH, mass ratio of zeolite to modify agent (m<SUB>Zeolite:m(Fe+Zr)</SUB>), mass ratio of Fe to Zr (Fe:Zr) to investigate their effects on the F⁻ adsorption. The performance of prepared Fe-Zr-Zeolite on F⁻ removal was examined through both statistic adsorption and dynamic adsorption. Results indicated that when the modified pH was 7, the Fe:Zr ratio was 1:1 and m<SUB>Zeolite:m(Fe+Zr)</SUB> was 1:2, the modified natural zeolites which was named Fe-Zr-Zeolite showed the best removal efficiency on F⁻. Fe-Zr-Zeolite could remove over 80% when the initial concentration was less than 20 mg/L and F⁻ adsorption followed pseudo-second-order adsorption kinetic and Langmuir adsorption isotherm, indicating that F⁻ adsorption by Fe-Zr-Zeolite was chemically dominated. Besides, Fe-Zr-Zeolite had better removal efficiency of F⁻ under acidic conditions than that under alkaline conditions, and the competing anions, typically, Cl-, NO₃⁻ and SO₄<SUP>2-</SUP> had negligible effect on F⁻ removal by Fe-Zr-Zeolite. The dynamic adsorption test demonstrated that in order to maintain the high removal efficiency of F⁻, the filling thickness of Fe-Zr-Zeolite should be at least 30 ㎝ and the small the flow rate is, the higher the F⁻ removal efficiency will be.

Zebra-Crossing Automatic Recognition and Early Warning for Intelligent Driving

Mingli Yang,Hua Shi,Yihui Chen,Xiangjin Ran,Chunhui Xu 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.8

Zebra-crossing Recognition is one of the essential parts of the visual based intelligent vehicle navigation or intelligent driving assistant system. In order to address the real-time and robustness, Zebra-crossing Recognition Method which is based on spatial-temporal correlation has been proposed. Firstly, calibrate a camera mounted on the vehicle by a practical method. Then, according to the prior knowledge such from GPS etc, a judgment whether it's in the Crossing area is made. Next, utilize the bipolar property of Zebra-crossing to extract features. Finally, the recognition results are obtained according to the model constraints. In this paper, proposed methods can improve real time identification of the zebra line by using spatial correlation, reduce the cost of recognition and lower errors during identification. The method overcomes some disadvantages of traditional identification approaches based upon video recognition, for instance higher cost and errors.

The work–life balance and psychosocial well-being of South Korean workers

Jae Won Yang,Chunhui Suh,Chae Kwan Lee,Byung Chul Son 대한직업환경의학회 2018 대한직업환경의학회지 Vol.30 No.-

Background: It is challenging to balance work and life, and little attention has been paid to the work.life balance and psychosocial well-being of South Koreans. We assessed the association between work.life balance and psychosocial well-being among paid Korean workers. Methods: This study was based on data from the fourth Korean Working Conditions Survey. We evaluated only paid workers, which constituted 30,649 of the total of 50,007 subjects surveyed. Poor work.life balance was defined based on the goodness of fit between working hours and social commitments. Well-being was measured using the World Health Organization WHO-5 index. Poisson regression with robust variances was used to calculate the estimated prevalence ratios (PRs) with confidence intervals. Results: Poor work.life balance was associated with poor psychosocial well-being (PR = 1.25; 95% CI 1.21 to 1.28) even after adjusting for work-related and individual characteristics. Poor well-being was associated with low-level job autonomy (PR = 1.06; 95% CI 1.03 to 1.09), working for ≥53 h per week (PR = 1.10; 95% CI 1.06 to 1.14), bluecollar status (PR = 1.16; 95% CI 1.11 to 1.21), low-level support at work (PR = 1.32; 95% CI 1.29 to 1.36), age ≥50 years (PR = 1.21; 95% CI 1.15 to 1.26), the female gender (95% CI PR = 1.04; 95% CI 1.01 to 1.07), and cohabitation (living with somebody) (PR = 1.08; 95% CI 1.04 to 1.12). Good well-being was associated with high-intensity work (PR = 0.96; 95% CI 0.94 to 0.99), being the secondary earner in a household (PR = 0.82; 95% CI 0.79 to 0.85), and higher income (PR = 0.75; 95% CI 0.71 to 0.79). Conclusion: Work.life balance was associated with psychosocial well-being after adjusting for both work-related and individual characteristics.

Emerging roles of centromeric RNAs in centromere formation and function

Qian Liu,Yang Liu,Qinghua Shi,Handong Su,Chunhui Wang,James A. Birchler,Fangpu Han 한국유전학회 2021 Genes & Genomics Vol.43 No.3

Background Centromeres are specialized chromosomal domains involved in kinetochore formation and faithful chromosome segregation. Despite a high level of functional conservation, centromeres are not identifed by DNA sequences, but by epigenetic means. Universally, centromeres are typically formed on highly repetitive DNA, which were previously considered to be silent. However, recent studies have shown that transcription occurs in this region, known as centromeric-derived RNAs (cenRNAs). CenRNAs that contribute to fundamental aspects of centromere function have been recently investigated in detail. However, the distribution, behavior and contributions of centromeric transcripts are still poorly understood. Objective The aim of this article is to provide an overview of the roles of cenRNAs in centromere formation and function. Methods We describe the structure and DNA sequence of centromere from yeast to human. In addition, we briefy introduce the roles of cenRNAs in centromere formation and function, kinetochore structure, accurate chromosome segregation, and pericentromeric heterochromatin assembly. Centromeric circular RNAs (circRNAs) and R-loops are rising stars in centromere function. CircRNAs have been successfully identifed in various species with the assistance of high-throughput sequencing and novel computational approaches for non-polyadenylated RNA transcripts. Centromeric R-loops can be identifed by the single-strand DNA ligation-based library preparation technique. But the molecular features and function of these centromeric R-loops and circRNAs are still being investigated. Conclusion In this review, we summarize recent fndings on the epigenetic regulation of cenRNAs across species, which would provide useful information about cenRNAs and interesting hints for further studies.

Numerical Simulations on Warm Forming of Stainless Steel with TRIP-Effect

Xiumei Wang,Chunhui Yang,Bernard Rolfe 한국소성가공학회 2010 기타자료 Vol.2010 No.6

In steels with TRIP-effect, a phase transformation from the retained-austenite to martensite occurs during forming, and it significantly affects hardening behaviours. Such an effect is sensitive to the amount of strain as well as the temperature variation. For materials with a strong TRIP-effect, new forming techniques are needed to develop that can lead to lighter and stronger components in automotive industry. This paper presents a coupled thermo-mechanical finite element modelling and simulation of a warm deep drawing of austenitic stainless steel (including a TRIP-effect) using LS-DYNA and temperature effect on forming process of such materials is investigated.

Formulations and Features of Person Selection in Organization Personnel Training Based on Supernetwork

Wei Sun,Chunhui Huo,Yang Yu 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.12

To investigate the reasonable method for selecting persons in organization personnel training, our study focuses on the formulation of personnel selection in organization personnel training based on knowledge supernetwork. First, this paper states the process of constructing organization training supernetwork and formulates the model for selecting single person. Subsequently, we establish the model for selecting multiple persons based on training knowledge supernetwork and analyze the complexity and the shortcomings in detail. Third, to improve the accuracy of personnel selection, we build the model for selecting multiple persons based on step-by-step method and analyze the complexity. Final, the proposed models are verified by an application case.