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Search Results: 1 - 10 of 118055 matches for " Chenghai Wang "
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STUDY ON RELATIONSHIP BETWEEN THE FROZEN-THAW PROCESS IN QINGHAI-XIZANG PLATEAU AND CIRCULATION IN EAST-ASIA
青藏高原季节冻融过程与东亚大气环流关系的研究

WANG CHENGHAI,
王澄海

地球物理学报 , 2003,
Abstract: 利用青藏高原46个气象站的最大冻土深度观测资料、中国160个气象站降水资料和NCAR/NCEP资料,对青藏高原冻土的季节性冻融过程进行合成分析,发现青藏高原土壤的季节冻融过程对青藏高原上空及东亚大气环流有显著的影响,在高原最大冻土深度较小的年份中,7月份,南亚高压强且偏西,500hPa印度低压强,西太平洋副热带高压弱且偏东,高原南部的东风较强;最大冻土深度较大的年份,南亚高压弱且偏东,印度低压弱,西太平洋副热带高压强且偏西,在不同的冻融年份,850hPa上纬向风的差异显著区反映了西南季风的活动,最大冻土深度与中国夏季(7月份)降水有3条显著相关带,雨带的分布与中国夏季平均雨带相吻合,由此,青藏高原季节冻融过程引起的水热变化是影响东亚气候的一个重要外源。
Spatial distributions and interannual variations of snow cover over China in the last 40 years

ChengHai Wang,ZhiLan Wang,Yang Cui,

寒旱区科学 , 2009,
Abstract:
The Impact of Warm Pool SST and General Circulation on Increased Temperature over the Tibetan Plateau

WANG Chenghai,YU Lian,HUANG Bo,

大气科学进展 , 2012,
Abstract: In this paper, the possible reason of Tibetan Plateau (TP) temperature increasing was investigated. An increase in Tmin (minimum temperature) plays a robust role in increased TP temperature, which is strongly related to SST over the warm pool of the western Pacific Ocean, the subtropical westerly jet stream (SWJ), and the tropical easterly upper jet stream (TEJ), and the 200-hPa zonal wind in East Asia. Composite analysis of the effects of SST, SWJ, and TEJ on pre- and post-abrupt changes in Ta (annual temperature) and Tmin over the TP shows remarkable differences in SST, SWJ, and TEJ. A lag correlation between TaTmin, SST, and SWJ/TEJ shows that changes in SST occur ahead of changes in Ta/Tmin by approximately one to three seasons. Partial correlations between Ta/Tmin, SST, and SWJ/TEJ show that the effect of SWJ on Ta/Tmin is more significant than the effect of SST. Furthermore, simulations with a community atmospheric model (CAM3.0) were performed, showing a remarkable increase in Ta over the TP when the SST increased by 0.5oC. The main increase in Ta and Tmin in the TP can be attributed to changes in SWJ. A possible mechanism is that changes in SST force the TEJ to weaken, move south, and lead to increased SWJ and movement of SWJ northward. Finally, changes in the intensity and location of the SWJ cause an increase in Ta/Tmin. It appears that TP warming is governed primarily by coherent TEJ and SWJ variations that act as the atmospheric bridges to remote SSTs in warm-pool forcing.
Periodic Heat Shock Accelerated the Chondrogenic Differentiation of Human Mesenchymal Stem Cells in Pellet Culture
Jing Chen, Chenghai Li, Sihong Wang
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0091561
Abstract: Osteoarthritis (OA) is one of diseases that seriously affect elderly people's quality of life. Human mesenchymal stem cells (hMSCs) offer a potential promise for the joint repair in OA patients. However, chondrogenic differentiation from hMSCs in vitro takes a long time (~6 weeks) and differentiated cells are still not as functionally mature as primary isolated chondrocytes, though chemical stimulations and mechanical loading have been intensively studied to enhance the hMSC differentiation. On the other hand, thermal stimulations of hMSC chondrogenesis have not been well explored. In this study, the direct effects of mild heat shock (HS) on the differentiation of hMSCs into chondrocytes in 3D pellet culture were investigated. Periodic HS at 41°C for 1 hr significantly increased sulfated glycosaminoglycan in 3D pellet culture at Day 10 of chondrogenesis. Immunohistochemical and Western Blot analyses revealed an increased expression of collagen type II and aggrecan in heat-shocked pellets than non heat-shocked pellets on Day 17 of chondrogenesis. In addition, HS also upregulated the expression of collagen type I and X as well as heat shock protein 70 on Day 17 and 24 of differentiation. These results demonstrate that HS accelerated the chondrogenic differentiation of hMSCs and induced an early maturation of chondrocytes differentiated from hMSCs. The results of this study will guide the design of future protocols using thermal treatments to facilitate cartilage regeneration with human mesenchymal stem cells.
Abrupt Change in Sahara Precipitation and the Associated Circulation Patterns  [PDF]
Celestin Sindikubwabo, Ruolin Li, Chenghai Wang
Atmospheric and Climate Sciences (ACS) , 2018, DOI: 10.4236/acs.2018.82017
Abstract: This study investigates the changes in inter-annual summer precipitation and the relationship with the atmospheric general circulation in the Sahara Desert occurred in the last 40 years (1971-2010). The results show that the summer precipitation undergone in drought recovery with a strong abrupt change at the end of 20th century. This change in Sahara precipitation is subsequently accompanied with the changes in the atmospheric circulation. The Sahara drought recovery is associated with a significant warming in the tropical and extratropical sea surface temperature, which led to the increase in moisture budget of the tropical African monsoon. The remarkable features such as the strengthening in Arctic high and mid-latitude upper level westerly wind, weakening in subpolar low and upper tropospheric zonal wind over North Africa have shown a distinct relationship with the Sahara precipitation changes.
Involvement of tumor necrosis factor-α in the upregulation of CXCR4 expression in gastric cancer induced by Helicobacter pylori
Chenghai Zhao, Xiaomei Lu, Xianmin Bu, Ning Zhang, Wei Wang
BMC Cancer , 2010, DOI: 10.1186/1471-2407-10-419
Abstract: Expression of CXCR4, TNF-α, IL-6 and IL-1β mRNA was determined by real-time PCR. CXCR4 protein expression was detected by Western blotting. Concentrations of TNF-α, IL-6 and IL-1β in cell culture supernatants were measured using the Quantikine Elisa kit. To abrogate TNF-α expression in HGC27 cells, TNF-α RNAi plasmid was used to transfect them.Levels of CXCR4 and TNF-α mRNA were significantly higher in H. pylori-positive gastric cancers (n = 19) compared to H. pylori-negative ones (n = 15). A subsequently Spearman's rank correlation test showed there was a positive correlation between the level of CXCR4 mRNA and that of TNF-α in 34 primary gastric cancers. Other results followed: Expression of CXCR4 and TNF-α was upregulated in gastric cancer cell MKN45 and HGC27 after infection with H. pylori 26695 (cag PAI+ ) or Tx30a (cag PAI- ); The induction of CXCR4 expression by H. pylori was inhibited significantly by a neutralizing TNF-α antibody, infliximab; CXCR4 expression was upregulated in MKN45 cells after treatment with exogenous TNF-α or co-culture with macrophage, and was downregulated in HGC27 cells after transfection with TNF-α RNAi plasmid. There was a significant increase in the migration of MKN45 cells treated with H. pylori 26695, and a strong inhibition when AMD 3100, a CXCR4 antagonist, or infliximab, was added.Our findings demonstrated that H. pylori upregulates CXCR4 expression in gastric cancer through TNF-α.It is well accepted that Helicobacter pylori (H. pylori) is a strong risk factor for the development of various gastric diseases, namely chronic gastritis, peptic ulcers, gastric mucosa-associated lymphoid tissue lymphoma and gastric cancer, and it is acknowledged that the interaction between H. pylori and epithelial cells contributes to such development. In fact, H. pylori infection induces inflammation in microenvironment of the stomach associated with induction of proinflammatory cytokines, such as tumor necrosis factor-α (TNF-α), interleukin-1β (
Downregulation of SFRP5 expression and its inverse correlation with those of MMP-7 and MT1-MMP in gastric cancer
Chenghai Zhao, Xianmin Bu, Ning Zhang, Wei Wang
BMC Cancer , 2009, DOI: 10.1186/1471-2407-9-224
Abstract: Expression of SFRP5, MMP-2, MMP-7, MMP-9 and MT1-MMP was determined by real-time PCR, RT-PCR or Western blotting. The methylation status of SFRP5 was detected by Methylation-specific PCR (MSP). Cell lines with SFRP5 methylation were demethylated by a DNA methyltransferase inhibitor 5-Aza-2'-deoxycytidine (DAC). KatoIII cells were transfected with pcDNA3.1 SFRP5 vector to strengthen SFRP5 expression. To abrogate SFRP5 expression in MKN1 cells, SFRP5 RNAi plamid was used to transfect them.SFRP5 expression was remarkably downregulated in 24 of 32 primary gastric cancer specimens, and even was not detectable in 5 of 8 gastric cancer cell lines. MMP-7 and MT1-MMP mRNA showed a stronger expression in these 24 specimens compared to the other 8 specimens. They also showed higher levels in gastric cancer cell lines AGS and NCI-N87 which had no SFRP5 expression, compared to MKN1 with strong SFRP5 expression. However, they were significantly downregulated, with SFRP5 expression restored in AGS and NCI-N87; and were considerably upregulated with it abrogated in MKN1.The results indicate there are frequent occurrences of downregualtion of SFRP5 expression in gastric cancer, primarily due to SFRP5 methylation. It seems to be responsible for the upregulation of MMP-7 expression and MT1-MMP expression on the ground that they are inversely correlated with SFRP5 expression.All the five secreted glycoproteins in Secreted Frizzled-Related Protein (SFRP) family contain a cysteine-rich domain (CRD) homologous to that of Wnt receptor Frizzled proteins. It is noted that via the CRD, they compete with the Frizzled proteins for Wnt binding, interfering with Wnt signaling. Downregulation of them can lead to aberrant activation of the Wnt pathway and induce tumorigenesis. SFRP1 is particularly well known for its frequent downregulation in human tumors, mainly due to hypermethylation of SFRP1 promoter [1-3]. Other members of this family, such as SFRP2, SFRP4 and SFRP5 [4,5], were also found to
Sensitivity of Regional Climate Model to Different Cumulus Parameterization Schemes in Simulation of the Tibetan Plateau Climate
区域气候模式对不同的积云参数化方案在青藏高原地区气候模拟中的敏感性研究

WANG Chenghai,YU Lian,
王澄海
,余莲

大气科学 , 2011,
Abstract: To examine the sensitivity of cumulus parameterization scheme in climate simulating over the Tibetan Plateau, three cumulus parameterization schemes in RegCM3 (The ICTP Regional Climate Model, V3.0), Anthes-Kuo (AK), Grell-Fritsch&Chappell (GFC), and MIT-Emanuel (MIT) are compared and analyzed in temperature and precipitation simulation over the Tibetan Plateau. The results show that AK, GFC and MIT schemes well reproduce the distribution of temperature and precipitation over the Tibetan Plateau, and the sp...
Numerical Simulation on Climate Effects of Freezing-Thawing Processes Using CCM3

Chenghai Wang,Guodong Cheng,Aijun Deng,Wenjie Dong,

寒旱区科学 , 2008,
Abstract: A parameterization of soil freezing-thawing physics for use in the land-surface model of the National Center for Atmospheric Research (NCAR) Community Climate Model (CCM3) is developed and evaluated. The new parameterization scheme has improved the representation of physical processes in the existing land surface model. Numerical simulations using CCM3 with improved land-surface processes and with the original land-surface processes are compared against the NCEP reanalysis. It is found that the CCM3 version using the improved land surface model shows significant improvements in simulating precipitation in China during the summer season, the general circulation over East Asia, and wind fields over the Tibet Plateau. For the summer season, the improved model was able to better simulate the Indian summer monsoon components, including the mean northerly wind in the upper troposphere and mean southerly wind in the lower troposphere.
Simulation analysis on characteristics of land surface over western Qinghai-Xizang Plateau during freezing–thawing period
ChengHai Wang,Rui Shi,Yang Cui,HongChao Zuo
寒旱区科学 , 2009,
Abstract: Using the Global Energy and Water Cycle Experiment—Asian Monsoon—Tibet Plateau Experiment (GAME-Tibet) observational data—from October 2002 through September 2003—of Gaize in the western Qinghai-Xizang Plateau (QXP), the land-surface characteristics of the Qinghai-Xizang Plateau are simulated by the improved land-surface model Common Land Model (CoLM). The results show that CoLM can reproduce the land-surface characteristics of plateau areas well. In the surface-energy balance of the western QXP in the winter half year, the sensible heat (SH) flux constituted the dominant energy, and the latent heat (LH, here and after) flux is very small. Although the LH flux nearly equals zero in freezing season, it cannot be ignored during the period of freezing–thawing in QXP. In the transition season from mid- to late-May, the frequent phase change of soil water that is caused by the freezing–thawing process leads to the increase of LH flux and decrease of the Bowen ratio. The simulation results also indicate that the changes of surface effective heat fluxes (SH and LH flux) are associated with precipitation and the frequent change between freezing and thawing processes in soil surface.
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