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Your search keyword '"Qin, Jianchun"' showing total 177 results
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177 results on '"Qin, Jianchun"'

12. Effects of Partially Replacing Mo with Nb on the Microstructure and Properties of High-Strength Low-Alloy Steel during Reverse Austenization.

Author

Luo, Liang, Zhang, Jiajun, Fu, Hao, Chen, Fuhu, Qin, Jianchun, and Li, Yimin

Subjects
LOW alloy steel, HEAT treatment, CRYSTAL grain boundaries, GRAIN refinement, ROLLED steel
Abstract

This study investigated the effects of partially replacing expensive Mo with cheaper Nb on the microstructure and properties of high-strength low-alloy (HSLA) steel during reverse austenisation. The mechanical properties of the steel in the hot-rolled state were lower with a partial replacement of Mo by Nb. However, after pre-tempering and reheating and quenching, the strength increased greatly while the ductility and toughness did not decrease much. Thus, the negative effects of replacing Mo with Nb were mostly alleviated, and a good balance between strength, ductility and toughness was achieved. After heat treatment, the mass percentage of precipitates increased substantially, which helped to pin grain boundaries during austenisation. The percent of high-angle grain boundaries greatly increased while the average effective grain size decreased, which improved grain refinement. The results showed that combining a partial replacement of Mo by Nb with heat treatment allows the microstructure and mechanical properties of HSLA steel to be effectively controlled while improving the balance between cost and performance. These findings provide valuable insights into the preparation and design of steels with similar microstructures. [ABSTRACT FROM AUTHOR]

Published
2024
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16. Mechanisms and transformed products of aflatoxin B1 degradation under multiple treatments: a review.

Author

Song, Chenggang, Yang, Jian, Wang, Yanduo, Ding, Gang, Guo, Lanping, and Qin, Jianchun

Subjects
AFLATOXINS, MYCOTOXINS, AGRICULTURAL productivity, AGRICULTURAL technology, CHEMICAL structure, HEPATOCELLULAR carcinoma, NATURAL products
Abstract

Aflatoxins, including aflatoxin B1, B2, G1, G2, M1, and M2, are one of the major types of mycotoxins that endangers food safety, human health, and contribute to the immeasurable loss of food and agricultural production in the world yearly. In addition, aflatoxin B1 (AFB1) mainly produced by Aspergilus sp. is the most potent of these compounds and has been well documented to cause the development of hepatocellular carcinoma in humans and animals. This paper reviewed the detoxification and degradation of AFB1, including analysis and summary of the major technologies in physics, chemistry, and biology in recent years. The chemical structure and toxicity of the transformed products, and the degradation mechanisms of AFB1 are overviewed and discussed in this presented review. In addition to the traditional techniques, we also provide a prospective study on the use of emerging detoxification methods such as natural products and photocatalysis. The purpose of this work is to provide reference for AFB1 control and detoxification, and to promote the development of follow-up research. [ABSTRACT FROM AUTHOR]

Published
2024
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33. Epoxycytochalasin H: An Endophytic Phomopsis Compound Induces Apoptosis in A2780 Cells Through Mitochondrial Damage and Endoplasmic Reticulum Stress

Author

Wang,Jiabin, Xu,Zhonghang, Hu,Xiaoqing, Yang,Yimeng, Su,Jing, Liu,Yanan, Zhou,Li, Qin,Jianchun, Zhang,Dawei, and Yu,Huimei

Subjects
OncoTargets and Therapy
Abstract

Jiabin Wang,1,2,* Zhonghang Xu,3,* Xiaoqing Hu,1 Yimeng Yang,1,2 Jing Su,1 Yanan Liu,1 Li Zhou,4 Jianchun Qin,5 Dawei Zhang,6 Huimei Yu1,6 1Key Laboratory of Pathobiology, Ministry of Education, Department of Pathophysiology, College of Basic Medical Sciences, Jilin University, Changchun 130021, People’s Republic of China; 2Department of Microbiology, College of Basic Medical Sciences, Jilin University, Changchun 130021, People’s Republic of China; 3Department of Gastrointestinal Colorectal and Anal Surgery, China-Japan Union Hospital, Jilin University, Changchun 130033, People’s Republic of China; 4Department of Obstetrics & Gynecology, The First Hospital of Jilin University, Changchun 130021, People’s Republic of China; 5College of Plant Sciences, Jilin University, Changchun, Jilin 130062, People’s Republic of China; 6Center of Animal Experiment, College of Basic Medical Sciences, Jilin University, Changchun 130021, People’s Republic of China*These authors contributed equally to this workCorrespondence: Dawei Zhang; Huimei YuCollege of Basic Medical Sciences, Jilin University, Changchun 130021, People’s Republic of ChinaEmail 13019225999@126.com; yuhuimei@jlu.edu.cnBackground: Natural compounds extracted from plants have been reported to have antitumor activity. A fungal metabolite from Phomopsis, identified as epoxycytochalasin H and isolated from the flowering plant Polygonatum sibiricum, was found to have significant antitumor activity. In this study, we report the antitumor effects and mechanism of action of epoxycytochalasin H in the ovarian cancer cell line A2780. Our data suggest that epoxycytochalasin H markedly reduces cell proliferation and induces apoptosis in ovarian cancer cells.Materials and Methods: The viability, apoptosis and colony formation of A2780 cells, treated with epoxycytochalasin H, were detected by MTT assay, nuclear staining, flow cytometry, and clone formation assay. MitoROS and mitochondrial membrane potentials were detected by MitoSOX staining and flow cytometry. The expression of proteins associated with apoptosis, autophagy, and endoplasmic reticulum stress, in A2780 cells treated with epoxycytochalasin H, was detected by Western blot. Effects of mitophagy were detected in Parkin-overexpressing 293T cells.Results: Our data suggested that epoxycytochalasin H could strongly reduce cell proliferation and induce apoptosis in ovarian cancer cell line A2780. Epoxycytochalasin H induced apoptosis through mitochondrial injury, mitophagy, and endoplasmic reticulum stress. Specifically, epoxycytochalasin H increased ROS level in cells, and in mitochondria, it decreased mitochondrial membrane potential, caused mitochondrial injury, activated macroautophagy and mitophagy, and subsequently induced apoptosis via the mitochondrial pathway. Additionally, it was discovered that epoxycytochalasin H could induce apoptosis more significantly in 293T cells overexpressing Parkin than in the parental cells. Thus, the mitophagy activated by epoxycytochalasin H could promote apoptosis. In addition, epoxycytochalasin H mediated endoplasmic reticulum stress-related apoptosis.Conclusion: Epoxycytochalasin H could promote apoptosis of human ovarian cancer A2780 cells by activating mitochondrial and endoplasmic reticulum stress-related apoptotic pathways.Keywords: natural compound, human ovarian cancer, apoptosis, mitochondrial damage, endoplasmic reticulum stress

Published
2020

42. The impact of tropical forcing on extratropical predictability in a simple global model

Author

Qin, Jianchun and Robinson, Walter A.

Subjects
Atmospheric circulation -- Analysis, Weather forecasting -- Methods, Ocean temperature -- Measurement, Earth sciences, Science and technology
Abstract

The impact of tropical forcing on the predictability of the extratropical atmosphere is studied. Using a two-layer spectral model, numerical experiments and diagnostic analyses have been carried out to examine the enhancement of predictability gained through knowledge of the tropical forcing. It turns out that knowing the tropical forcing induces a modest but significant improvement in extended-range predictions in middle/high latitudes. The enhancement of predictability can be locally large in a zonally asymmetric climate. A robust response to tropical forcing in the model, however, does not necessarily imply a strong impact on extratropical predictions.

Published
1995

43. AIRS Data Subsetting Service at the Goddard Earth Sciences (GES) DISC/DAAC

Author

Vicente, Gilberto A, Qin, Jianchun, Li, Jason, Gerasimov, Irina, and Savtchenko, Andrey

Subjects
Earth Resources And Remote Sensing
Abstract

The AIRS mission, as a combination of the Atmospheric Infrared Sounder (AIRS), the Advanced Microwave Sounding Unit (AMSU) and the Humidity Sounder for Brazil (HSB), brings climate research and weather prediction into 21st century. From NASA' Aqua spacecraft, the AIRS/AMSU/HSB instruments measure humidity, temperature, cloud properties and the amounts of greenhouse gases. The AIRS also reveals land and sea- surface temperatures. Measurements from these three instruments are analyzed . jointly to filter out the effects of clouds from the IR data in order to derive clear-column air-temperature profiles and surface temperatures with high vertical resolution and accuracy. Together, they constitute an advanced operational sounding data system that have contributed to improve global modeling efforts and numerical weather prediction; enhance studies of the global energy and water cycles, the effects of greenhouse gases, and atmosphere-surface interactions; and facilitate monitoring of climate variations and trends. The high data volume generated by the AIRS/AMSU/HSB instruments and the complexity of its data format (Hierarchical Data Format, HDF) are barriers to AIRS data use. Although many researchers are interested in only a fraction of the data they receive or request, they are forced to run their algorithms on a much larger data set to extract the information of interest. In order to better server its users, the GES DISC/DAAC, provider of long-term archives and distribution services as well science support for the AIRS/AMSU/HSB data products, has developed various tools for performing channels, variables, parameter, spatial and derived products subsetting, resampling and reformatting operations. This presentation mainly describes the web-enabled subsetting services currently available at the GES DISC/DAAC that provide subsetting functions for all the Level 1B and Level 2 data products from the AIRS/AMSU/HSB instruments.

Published
2004

44. On the Rossby wave source and the steady linear response to tropical forcing

Author

Qin, Jianchun and Robinson, Walter A.

Subjects
Rossby waves -- Research, Atmospheric thermodynamics -- Research, Earth sciences, Science and technology
Abstract

A two-level spectral model with a zonally homogeneous climate is used to study the steady response of a spherical atmosphere to tropical heating. Solutions are obtained by both averaging the time integration of the model and solving for the linear steady response. It is found that the Rossby wave source (RWS) from a simple tropical heat source exhibits a relatively complicated horizontal structure that extends from the tropics into extratropical regions. The strong extratropical component of the RWS is important for the steady response in middle and high latitudes. A decomposition of the solution using separately the components of the RWS in tropical and extratropical regions shows that the responses to the tropical and extratropical RWSs tend to cancel in middle and high latitudes. The extratropical component of the RWS may be understood by quasigeostrophic dynamics.

Published
1993

45. Bioactive Monomer and Polymer Polyketides from Edible Mushroom Cortinarius caerulescensas Glutamate Dehydrogenase Inhibitors and Antioxidants

Author

Song, Chenggang, Wu, Mingyue, Zhang, Yanxin, Li, Jie, Yang, Jian, Wei, Dongsheng, Li, He, Guo, Lanping, and Qin, Jianchun

Abstract

Two new polyketides named rufoolivacin Eand viocristin B, a new natural product named 1-hydroxy-3,6,8-trimethoxyanthraquinone, and 13 known compounds were isolated from edible mushroom Cortinarius purpurascensin this work. Their structures were assigned on the basis of high-resolution electrospray ionization mass spectrometry, 1D and 2D nuclear magnetic resonance, and electronic circular dichroism data. Notably, the enzyme activity test on glutamate dehydrogenase indicated that 1, 3, 4, 5, 6, 10, 11, and 15displayed an excellent inhibition effect. Further kinetic studies showed that the most potent compounds, 4and 10, possess great potential as competitive inhibitors of glutamate dehydrogenase. Molecular docking and computational chemistry were applied to illustrate the binding mechanism in detail. 2,2-Diphenyl-1-picrylhydrazyl and reactive oxygen species assay results showed that compounds 1, 2, 3, and 8exhibited significant antioxidant activities with IC50values of 7.0 ± 0.3, 8.6 ± 0.1, 7.5 ± 0.1, and 2.8 ± 0.2 μg mL–1, respectively. Thus, Cortinarius caerulescensrepresents a novel resource of these polyketides to be utilized in food selection and drug discovery.

Published
2022
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