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- 2019
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Wang, Mengmeng, et al.
(författare)
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Statistical analysis of whistler precursors upstream of foreshock transient shocks : MMS observations
- 2024
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Ingår i: Geophysical Research Letters. - : American Geophysical Union (AGU). - 0094-8276 .- 1944-8007. ; 51:8
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Tidskriftsartikel (refereegranskat)abstract
- Using the high-time-resolution data from the Magnetospheric Multiscale mission, precursor waves upstream of foreshock transient (FT) shocks are statistically investigated using the four-spacecraft timing method. The wave frequencies and wave vectors determined in the plasma rest frame (PRF) are shown to follow the cold plasma dispersion relation for whistler waves. Combining with the feature of the right-hand polarization in the PRF, the precursors are identified as whistler-mode waves around the lower hybrid frequency. The occurrence of whistler precursors is independent of the Alfvén Mach number and the FT shock normal angle. More importantly, all the whistler precursors have group velocities pointing upstream in the shock frame, suggesting the dispersive radiation to be a possible generation mechanism. The study improves the understanding of not only the whistler precursors but also the overall FT shock dynamics.
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| 3. |
- Qi, Qibin, et al.
(författare)
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FTO genetic variants, dietary intake and body mass index : insights from 177 330 individuals
- 2014
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 23:25, s. 6961-6972
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Tidskriftsartikel (refereegranskat)abstract
- FTO is the strongest known genetic susceptibility locus for obesity. Experimental studies in animals suggest the potential roles of FTO in regulating food intake. The interactive relation among FTO variants, dietary intake and body mass index (BMI) is complex and results from previous often small-scale studies in humans are highly inconsistent. We performed large-scale analyses based on data from 177 330 adults (154 439 Whites, 5776 African Americans and 17 115 Asians) from 40 studies to examine: (i) the association between the FTO-rs9939609 variant (or a proxy single-nucleotide polymorphism) and total energy and macronutrient intake and (ii) the interaction between the FTO variant and dietary intake on BMI. The minor allele (A-allele) of the FTO-rs9939609 variant was associated with higher BMI in Whites (effect per allele = 0.34 [0.31, 0.37] kg/m(2), P = 1.9 × 10(-105)), and all participants (0.30 [0.30, 0.35] kg/m(2), P = 3.6 × 10(-107)). The BMI-increasing allele of the FTO variant showed a significant association with higher dietary protein intake (effect per allele = 0.08 [0.06, 0.10] %, P = 2.4 × 10(-16)), and relative weak associations with lower total energy intake (-6.4 [-10.1, -2.6] kcal/day, P = 0.001) and lower dietary carbohydrate intake (-0.07 [-0.11, -0.02] %, P = 0.004). The associations with protein (P = 7.5 × 10(-9)) and total energy (P = 0.002) were attenuated but remained significant after adjustment for BMI. We did not find significant interactions between the FTO variant and dietary intake of total energy, protein, carbohydrate or fat on BMI. Our findings suggest a positive association between the BMI-increasing allele of FTO variant and higher dietary protein intake and offer insight into potential link between FTO, dietary protein intake and adiposity.
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| 4. |
- Wang, Zhigang, et al.
(författare)
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Decreased Splenic CD4(+) T-Lymphocytes in Apolipoprotein M Gene Deficient Mice
- 2015
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Ingår i: BioMed Research International. - : Hindawi Limited. - 2314-6133 .- 2314-6141.
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Tidskriftsartikel (refereegranskat)abstract
- Spleen T-lymphocytes, especially CD4(+) T-cells, have been demonstrated to be involved in broad immunomodulation and host-defense activity in vivo. Apolipoprotein M gene (apoM) may have an important role in the regulation of immunoprocess and inflammation, which could be hypothesized to the apoM containing sphingosine-1-phosphate (S1P). In the present study we demonstrate that the splenic CD4(+) T-lymphocytes were obviously decreased in the apoM gene deficient (apoM(-/-)) mice compared to the wild type (apoM(+/+)). Moreover, these mice were treated with lipopolysaccharide (LPS) and it was found that even more pronounced decreasing CD4(+) T-lymphocytes occurred in the spleen compared to the apoM(+/+) mice. The similar phenomena were found in the ratio of CD4(+)/CD8(+) T-lymphocytes. After administration of LPS, the hepatic mRNA levels of tumor necrosis factor-alpha (TNF-alpha) and monocyte chemotactic protein-1 (MCP-1) were markedly increased; however, there were no statistical differences observed between apoM(+/+) mice and apoM(-/-) mice. The present study demonstrated that apoM might facilitate the maintenance of CD4(+) T-lymphocytes or could modify the T-lymphocytes subgroups in murine spleen, which may further explore the importance of apoM in the regulation of the host immunomodulation, although the detailed mechanism needs continuing investigation.
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| 5. |
- Zhou, Xu-Zhi, et al.
(författare)
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On the Origin of Perpendicular Ion Anisotropy Inside Dipolarizing Flux Bundles
- 2019
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Ingår i: Journal of Geophysical Research - Space Physics. - 2169-9380 .- 2169-9402. ; 124:6, s. 4009-4021
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Tidskriftsartikel (refereegranskat)abstract
- Perpendicular anisotropy of suprathermal ions, observed inside some of the dipolarizing flux bundles (DFBs) in the magnetotail plasma sheet, have been attributed to successive, betatron-type accelerations during the DFB entry of ambient ions. It has been unclear, however, where and how these ions enter the DFBs. The proposed locations include the DFB flanks where cross-tail drifting ions are picked up, and the DFB leading edge with sharp magnetic field gradient (the dipolarization front, DF). Here we examine the latter scenario, based on a simplistic, test particle approach, to predict the preferred conditions for the appearance of the DFB ion anisotropy. Our model predicts that the ion anisotropy would be stronger at locations closer to the neutral sheet and would appear preferentially in the DFB dawnside and central sectors rather than the duskside sector. We also predict that the ion anisotropy would more likely be observed in DFBs with higher propagation speeds. These properties can be understood in our model by the dawnward drift of ions during their DF penetration (attributed to the large magnetic gradient). To examine these predictions, we carry out a statistical survey based on observations from the THEMIS (Time History of Events and Macroscale Interactions during Substorms) mission, to show a clear dependence of the ion anisotropy on spacecraft location and the DFB propagation speed. These findings, therefore, are consistent with the scenario that the perpendicular ion anisotropy originates from the ion acceleration and penetration across sharp DFs.
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| 6. |
- Zhu, Zhenshuo, et al.
(författare)
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Histone demethylase complexes KDM3A and KDM3B cooperate with OCT4/SOX2 to define a pluripotency gene regulatory network
- 2021
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Ingår i: The FASEB Journal. - : John Wiley & Sons. - 0892-6638 .- 1530-6860. ; 35:6
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Tidskriftsartikel (refereegranskat)abstract
- The pluripotency gene regulatory network of porcine induced pluripotent stem cells(piPSCs), especially in epigenetics, remains elusive. To determine the biological function of epigenetics, we cultured piPSCs in different culture conditions. We found that activation of pluripotent gene- and pluripotency-related pathways requires the erasure of H3K9 methylation modification which was further influenced by mouse embryonic fibroblast (MEF) served feeder. By dissecting the dynamic change of H3K9 methylation during loss of pluripotency, we demonstrated that the H3K9 demethylases KDM3A and KDM3B regulated global H3K9me2/me3 level and that their co-depletion led to the collapse of the pluripotency gene regulatory network. Immunoprecipitation-mass spectrometry (IP-MS) provided evidence that KDM3A and KDM3B formed a complex to perform H3K9 demethylation. The genome-wide regulation analysis revealed that OCT4 (O) and SOX2 (S), the core pluripotency transcriptional activators, maintained the pluripotent state of piPSCs depending on the H3K9 hypomethylation. Further investigation revealed that O/S cooperating with histone demethylase complex containing KDM3A and KDM3B promoted pluripotency genes expression to maintain the pluripotent state of piPSCs. Together, these data offer a unique insight into the epigenetic pluripotency network of piPSCs.
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