| 1. |
- Tao, Jianmin, et al.
(författare)
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First-principles study of the binding energy between nanostructures and its scaling with system size
- 2018
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Ingår i: Physical Review B. - 2469-9969 .- 2469-9950. ; 97:15
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Tidskriftsartikel (refereegranskat)abstract
- The equilibrium van der Waals binding energy is an important factor in the design of materials and devices. However, it presents great computational challenges for materials built up from nanostructures. Here we investigate the binding-energy scaling behavior from first-principles calculations. We show that the equilibrium binding energy per atom between identical nanostructures can scale up or down with nanostructure size, but can be parametrized for large N with an analytical formula (in meV/atom), Eb/N=a+b/N+c/N2+d/N3, where N is the number of atoms in a nanostructure and a, b, c, and d are fitting parameters, depending on the properties of a nanostructure. The formula is consistent with a finite large-size limit of binding energy per atom. We find that there are two competing factors in the determination of the binding energy: Nonadditivities of van der Waals coefficients and center-to-center distance between nanostructures. To decode the detail, the nonadditivity of the static multipole polarizability is investigated from an accurate spherical-shell model. We find that the higher-order multipole polarizability displays ultrastrong intrinsic nonadditivity, no matter if the dipole polarizability is additive or not.
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| 2. |
- Bai, Ru, et al.
(författare)
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The NF-κB-modulated miR-19a-3p enhances malignancy of human ovarian cancer cells through inhibition of IGFBP-3 expression
- 2019
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Ingår i: Molecular Carcinogenesis. - : Wiley. - 0899-1987 .- 1098-2744. ; 58:12, s. 2254-2265
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Tidskriftsartikel (refereegranskat)abstract
- Ovarian cancer is the most lethal gynecologic malignancy due to the lack of symptoms until advanced stages, and new diagnosis and treatment strategy is in urgent need. In this study, we found higher expression of miR-19a-3p in ovarian cancer tissues compared with that in the adjacent normal tissues. By chromatin immunoprecipitation (ChIP) and electrophoretic mobility shift assay (EMSA) analysis, we showed that nuclear factor-kappaB (NF-κB) binds to the promoter of miR-19a-3p, leading to reduced expression in ovarian cancer cells. Further study indicated that miR-19a-3p inhibits the expression of insulin-like growth factor binding protein-3 (IGFBP-3), resulting in enhanced growth and migration of ovarian cancer cells in vitro and tumor growth in vivo. These results showed that miR-19a-3p enhances the oncogenesis of ovarian cancer through inhibition of IGFBP-3 expression, and which can be inhibited by NF-κB, suggesting an NF-κB/miR-19a-3p/IGFBP-3 pathway in the oncogenesis of ovarian cancer, which expands our understanding of ovarian cancer and they may contribute to the development of new diagnosis and treatment of ovarian cancer.
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| 3. |
- Cui, Xinjuan, et al.
(författare)
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Radiative absorption enhancement from coatings on black carbon aerosols
- 2016
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 551, s. 51-56
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Tidskriftsartikel (refereegranskat)abstract
- The radiative absorption enhancement of ambient black carbon (BC), by light-refractive coatings of atmospheric aerosols, constitutes a large uncertainty in estimates of climate forcing. The direct measurements of radiative absorption enhancement require the experimentally-removing the coating materials in ambient BC-containing aerosols, which remains a challenge. Here, the absorption enhancement of the BC core by non-absorbing aerosol coatings was quantified using a two-step removal of both inorganic and organic matter coatings of ambient aerosols. The mass absorption cross-section (MAC) of decoated/pure atmospheric BC aerosols of 4.4 +/- 0.8 m(2)g(-1) was enhanced to 9.6 +/- 1.8 m(2)g(-1) at 678-nm wavelength for ambiently-coated BC aerosols at a rural Northern China site. The enhancement of MAC (E-MAC) rises from 1.4 +/- 0.3 in fresh combustion emissions to similar to 3 for aged ambient China aerosols. The three-week high-intensity campaign observed an average E-MAC of 2.25 +/- 0.55, and sulfates were primary drivers of the enhanced BC absorption.
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| 4. |
- Xiong, Jiantuan, et al.
(författare)
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Hypermethylation of endoplasmic reticulum disulfide oxidase 1α leads to trophoblast cell apoptosis through endoplasmic reticulum stress in preeclampsia
- 2018
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Ingår i: Journal of Cellular Biochemistry. - : Wiley. - 0730-2312 .- 1097-4644. ; 119:10, s. 8588-8599
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Tidskriftsartikel (refereegranskat)abstract
- Abnormal trophoblast cell apoptosis is implicated in the pathogenesis of pregnancy-related disorders including preeclampsia (PE), and endoplasmic reticulum (ER) stress has been considered as a novel pathway in the regulation of cell apoptosis. In this study, we observed that both apoptosis and ER stress are triggered in trophoblast cells under hypoxia as well as in the placenta of PE rats. Quantitative polymerase chain reaction and Western blot analysis showed that the expression of endoplasmic reticulum disulfide oxidase 1α (ERO1α) is suppressed in trophoblast cells under hypoxia due to the hypermethylation of the ERO1α promoter region, and the inhibition of ERO1α expression plays an important role in ER stress and trophoblast cell apoptosis. Furthermore, we found that DNA methyltransferase 1 (DNMT1) is a key methyltransferase for DNA methylation in the regulation of ERO1α expression, and the binding level of DNMT1 to the ERO1α promoter is markedly elevated under hypoxia although DNMT1 expression is inhibited by hypoxia, suggesting that the binding level of DNMT1 to the ERO1α promoter region rather than the DNMT1 expression level contributes to the hypermethylation of ERO1α. Taken together, these results demonstrate that the hypermethylation of ERO1α mediated by increased binding of DNMT1 to the ERO1α promoter leads to trophoblast cell apoptosis through ER stress in the placenta of PE rats, which shed insight into the etiology of PE and might present a validated therapeutic target for the treatment of PE.
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| 5. |
- Yao, Lei, et al.
(författare)
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Atmospheric new particle formation from sulfuric acid and amines in a Chinese megacity
- 2018
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 361:6399, s. 278-281
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Tidskriftsartikel (refereegranskat)abstract
- Atmospheric new particle formation (NPF) is an important global phenomenon that is nevertheless sensitive to ambient conditions. According to both observation and theoretical arguments, NPF usually requires a relatively high sulfuric acid (H2SO4) concentration to promote the formation of new particles and a low preexisting aerosol loading to minimize the sink of new particles. We investigated NPF in Shanghai and were able to observe both precursor vapors (H2SO4) and initial clusters at a molecular level in a megacity. High NPF rates were observed to coincide with several familiar markers suggestive of H2SO4-dimethylamine (DMA)water (H2O) nucleation, including sulfuric acid dimers and H2SO4-DMA clusters. In a cluster kinetics simulation, the observed concentration of sulfuric acid was high enough to explain the particle growth to similar to 3 nanometers under the very high condensation sink, whereas the subsequent higher growth rate beyond this size is believed to result fromthe added contribution of condensing organic species. These findings will help in understanding urban NPF and its air quality and climate effects, as well as in formulating policies to mitigate secondary particle formation in China.
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