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121 results on '"Wang, Yun-Bo"'

5. Crystal structure of camptothecin, C20H16N2O4

Author

Tan Zhuo-Jie, Wang Yun-Bo, Yang Quan-Nu, Li Yao-Lan, Wang Guo-Cai, Ouyang Yong-Zhong, and Li Guo-Qiang

Subjects
1558968, Physics, QC1-999, Crystallography, QD901-999
Abstract

C20H16N2O4, monoclinic, P21 (no. 4), a = 8.0094(5) Å, b = 6.7689(3) Å, c = 29.577(2) Å, β = 95.809(6)°, V =1595.27(16) Å3, Z = 4, Rgt(F) = 0.0457, wRref(F2) = 0.1209, T = 293 K.

Published
2018
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10. Asymptotic Behavior of Least Energy Solutions for a Fractional Laplacian Eigenvalue Problem on ℝN.

Author

Wang, Yun Bo, Zeng, Xiao Yu, and Zhou, Huan Song

Subjects
EIGENVALUES, BLOWING up (Algebraic geometry)
Abstract

We are interested in the existence and asymptotic behavior for the least energy solutions of the following fractional eigenvalue problem (P) (− Δ) s u + V (x) u = μ u + a m (x) ∣ u ∣ 4 s N u , ∫ ℝ N ∣ u ∣ 2 d x = 1 , u ∈ H s (ℝ N) , where s ∈ (0, 1), μ ∈ ℝ, a > 0, V (x) and m(x) are L∞(ℝN) functions with N ≥ 2. We prove that there is a threshold a s ∗ > 0 such that problem (P) has a least energy solution ua (x) for each a ∈ (0 , a s ∗) and ua blows up, as a ↗ a s ∗ , at some point x0 ∈ ℝN, which makes V (x0) be the minimum and m(x0) be the maximum. Moreover, the precise blowup rates for ua are obtained under suitable conditions on V (x) and m(x). [ABSTRACT FROM AUTHOR]

Published
2023
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19. Fabrication and Measurement of Flexible Polymer Aerogel and Factors Affecting its Thermal Conductivity

Author

Wang, Jia Zhen, Du, Jing, and Wang, Yun Bo

Abstract

Silica aerogels are the most widely studied type of aerogel. However, its application still suffers from low mechanical strength and high production cost. The paper studies the use of recyclable PVC as the backbone material of the aerogel and introduces an economically friendly fabrication process of flexible PVC aerogel using sol-gel technique and ambient drying instead of the CO2 critical drying. Three different types of PVC powder with the molecule weight of 43000, 48000, and 80000 respectively are chosen and dissolved in DMF in five different concentrations-0.2, 0.4, 0.6, 0.8, and 1.0 g (mL)-1. The lowest thermal conductivity of the aerogel is measured using hot-wire method as 0.0323W(m*K)-1, which is made of PVC with molecule weight of 80000 in a concentration of 0.4g (mL)-1. The analysis based on SEM pictures shows that PVC type and concentration would greatly influence aerogel’s structure thus affecting its thermal conductivity. The optimal solution for producing low thermal conductivity aerogel is to use PVC powder with low molecule weight with a concentration between 0.2 and 0.6 g (mL)-1.

Published
2021
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40. Crystal structure of camptothecin, C20H16N2O4.

Author

Tan, Zhuo-Jie, Wang, Yun-Bo, Yang, Quan-Nu, Li, Guo-Qiang, Li, Yao-Lan, Wang, Guo-Cai, and Ouyang, Yong-Zhong

Subjects
CAMPTOTHECIN, CRYSTAL structure, HYDROGEN atom, CAMPTOTHECA acuminata, CLINICAL trials, CHINESE medicine, ANTINEOPLASTIC agents, PYRANONES
Abstract

C20H16N2O4, monoclinic, P21 (no. 4), a = 8.0094(5) Å, b = 6.7689(3) Å, c = 29.577(2) Å, β = 95.809(6)°, V =1595.27(16) Å3, Z = 4, Rgt(F) = 0.0457, wRref(F2) = 0.1209, T = 293 K. [ABSTRACT FROM AUTHOR]

Published
2018
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46. Influence of Fe in the local Structure of Perovskite Compound La 2/3 Ca 1/3 Fe 1- x Mn x O 3

Author

Wang Hui-Yao, Wang Tian-Min, Wei Long, Wang Yun-Bo, Zhang Tian-Bao, Yue Yong, and Cao Guo-Hui

Subjects
Materials science, Condensed matter physics, Spin states, Doping, Analytical chemistry, General Physics and Astronomy, Electronic structure, Local structure, Spectral line, visual_art, Mössbauer spectroscopy, visual_art.visual_art_medium, Ceramic, Perovskite (structure)
Abstract

The ceramic samples with nominal composition of La2/3Ca1/3Mn1-xFexO3 (0.01 ≤ x ≤ 0.20) were prepared by solid state reaction method. The effect of Fe doping on the Mn site was measured by the positron annihilation technique and Mossbauer spectroscopy. Upon doping, no appreciable structure change and electronic structure change in Mn-O plane were observed in the series of compounds. The Mossbauer parameters show that the iron probe has stable 3+ valance with the high spin state in all samples. Moreover, by examining the shape of the spectra, the tendency can be found that the isomer shift and quadruploe splitting increase with the increasing Fe+3 content. This phenomenon shows the local lattice distortion and the localization of d-electrons with the increasing Fe-doping content.

Published
2000
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47. In vivo hair growth-stimulating effect of medicinal plant extract on BALB/c nude mice.

Author

Begum, Shahnaz, Gu, Li-Juan, Lee, Mi-Ra, Li, Zheng, Li, Jing-Jie, Hossain, Md. Jamil, Wang, Yun-Bo, and Sung, Chang Keun

Subjects
HAIR physiology, MEDICINAL plants, PLANT extracts, LABORATORY mice, CHRYSANTHEMUMS, ASTERACEAE
Abstract

Context: Chrysanthemum zawadskii var. latilobum (Asteraceae) (CZ) and Polygonum multiflorum Thunb. (Polygonaceae) (PM) have been used traditionally to treat different systemic diseases and acclaimed for various biological activities including hair growth. Objective: This study investigates the hair restoration efficacy of selected medicinal plant extracts on nude mice. Materials and methods: Nude mice genetically predisposed to pattern balding were used in this study. Topical methanol extracts of CZ and PM (10 mg/mouse/d) with standardized vehicle formulation, only vehicle (propylene glycol:ethanol:dimethyl sulfoxide, 67:30:3% v/v) and Minoxidil (2%) were applied daily for 40 consecutive days. Results: In our study, the maximum hair score (2.5 ± 0.29) was obtained in the CZ-treated group. Histological observation revealed a significant increase ( p < 0.001) in the number of hair follicles (HF) in CZ-treated mice (58.66 ± 3.72) and Minoxidil-treated mice (40 ± 2.71). Subsequently, immunohistochemical analysis also confirmed the follicular keratinocyte proliferation by detection of BrdU-labeling, S-phase cells in Minoxidil and CZ-treated mouse follicular bulb and outer root sheaths. Conclusion: Our study revealed the underlying mechanism of stimulating hair growth in athymic nude mice by repair the nu/nu follicular keratin differentiation defect. Thus, the topical application of CZ may represent a novel strategy for the management and therapy of certain forms of alopecia. [ABSTRACT FROM AUTHOR]

Published
2015
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