17,644 research outputs found

    Roles of TGFβ and FGF signals during growth and differentiation of mouse lens epithelial cell in vitro.

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    Transforming growth factor β (TGFβ) and fibroblast growth factor (FGF) signaling pathways play important roles in the proliferation and differentiation of lens epithelial cells (LECs) during development. Low dosage bFGF promotes cell proliferation while high dosage induces differentiation. TGFβ signaling regulates LEC proliferation and differentiation as well, but also promotes epithelial-mesenchymal transitions that lead to cataracts. Thus far, it has been difficult to recapitulate the features of germinative LECs in vitro. Here, we have established a LEC culture protocol that uses SB431542 (SB) compound to inhibit TGFβ/Smad activation, and found that SB treatment promoted mouse LEC proliferation, maintained LECs' morphology and distinct markers including N-cadherin, c-Maf, Prox1, and αA-, αB-, and β-crystallins. In contrast, low-dosage bFGF was unable to sustain those markers and, combined with SB, altered LECs' morphology and β-crystallin expression. We further found that Matrigel substrate coatings greatly increased cell proliferation and uniquely affected β-crystallin expression. Cultured LECs retained the ability to differentiate into γ-crystallin-positive lentoids by high-dosage bFGF treatment. Thus, a suppression of TGFβ/Smad signaling in vitro is critical to maintaining characteristic features of mouse LECs, especially expression of the key transcription factors c-Maf and Prox1

    2017-19 Consumption Inequality in Urban China, 1995-2013

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    We use 1995, 2002 and 2013 CHIP data to investigate the urban household consumption expenditure inequality. The overall inequality of urban household consumption expenditure measured by Gini coefficient slightly decreases from 0.33 in 1995 to 0.32 in 2002, but increases to 0.36 in 2013, which follows the same trend with that of urban income but is severer. However, the percentile ratio of p90/p10 shows that consumption inequality increases all the time. Besides, the inequality of basic food consumption is much smaller than the overall consumption, its contribution to the overall consumption inequality decreases from 20% in 1995 and 2002 to 15% by 2013, and its share also decreases steadily from 34% in 1995 to 30% in 2002 and further to 24% in 2013, and finally its share steadily decreases as the overall consumption level moving up the distribution in each of the three years. The inequality of housing consumption is much larger than overall consumption but decreasing over time, its contribution to the overall consumption inequality increases 35% in earlier two years to 40% by 2013, and its share also sharply increases from 23% in 1995 to 30% in 2002 and further to 38% in 2013, besides its share shows upward sloping as overall consumption level increases in each of the three years

    Associations of Muscle Mass and Strength with All-Cause Mortality among US Older Adults

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    INTRODUCTION: Recent studies suggested that muscle mass and muscle strength may independently or synergistically affect aging-related health outcomes in older adults; however, prospective data on mortality in the general population are sparse. METHODS: We aimed to prospectively examine individual and joint associations of low muscle mass and low muscle strength with all-cause mortality in a nationally representative sample. This study included 4449 participants age 50 yr and older from the National Health and Nutrition Examination Survey 1999 to 2002 with public use 2011 linked mortality files. Weighted multivariable logistic regression models were adjusted for age, sex, race, body mass index (BMI), smoking, alcohol use, education, leisure time physical activity, sedentary time, and comorbid diseases. RESULTS: Overall, the prevalence of low muscle mass was 23.1% defined by appendicular lean mass (ALM) and 17.0% defined by ALM/BMI, and the prevalence of low muscle strength was 19.4%. In the joint analyses, all-cause mortality was significantly higher among individuals with low muscle strength, whether they had low muscle mass (odds ratio [OR], 2.03; 95% confidence interval [CI], 1.27-3.24 for ALM; OR, 2.53; 95% CI, 1.64-3.88 for ALM/BMI) or not (OR, 2.66; 95% CI, 1.53-4.62 for ALM; OR, 2.17; 95% CI, 1.29-3.64 for ALM/BMI). In addition, the significant associations between low muscle strength and all-cause mortality persisted across different levels of metabolic syndrome, sedentary time, and LTPA. CONCLUSIONS: Low muscle strength was independently associated with elevated risk of all-cause mortality, regardless of muscle mass, metabolic syndrome, sedentary time, or LTPA among US older adults, indicating the importance of muscle strength in predicting aging-related health outcomes in older adults

    Eta absorption by mesons

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    Using the [SU(3)L×SU(3)R]global×[SU(3)V]local[SU(3)_{\mathrm{L}} \times SU(3)_{\mathrm{R}}]_{\mathrm{global}% }\times [SU(3)_V]_{\mathrm{local}} chiral Lagrangian with hidden local symmetry, we evaluate the cross sections for the absorption of eta meson (η% \eta) by pion (π\pi), rho (ρ\rho), omega (ω\omega), kaon (KK), and kaon star (KK^*) in the tree-level approximation. With empirical masses and coupling constants as well as reasonable values for the cutoff parameter in the form factors at interaction vertices, we find that most cross sections are less than 1 mb, except the reactions ρηKKˉ(KˉK)\rho\eta\to K\bar K^*(\bar KK^*), ωηKKˉ(KˉK)\omega\eta\to K\bar K^*(\bar KK^*), KηρKK^*\eta\to\rho K, and KηωKK^*\eta\to\omega K, which are a few mb, and the reactions πηKKˉ\pi\eta\to K\bar K and KηπKK\eta\to\pi K, which are more than 10 mb. Including these reactions in a kinetic model based on a schematic hydrodynamic description of relativistic heavy ion collisions, we find that the abundance of eta mesons likely reaches chemical equilibrium with other hadrons in nuclear collisions at the Relativistic Heavy Ion Collider.Comment: 29 pages, 10 figures, version to appear in Nucl. Phys.

    The effects of the state sector on wage inequality in urban China: 1988 - 2007

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    This paper examines the effects of state sector domination on wage inequality in urban China. Using Chinese Household Income Project surveys, we conduct two exercises: with quantile regression analysis, we identify wage gaps across the distribution and over time; and we employ the Machado and Mata (2005) decomposition to investigate how urban wage inequality was affected by the changes in wage structure and employment share of the state sector. We find that since the radical state sector reforms designed to reduce over-staffing and improve efficiency since the late 1990s, urban wage gaps were narrowed due to the reduction of employment share in the state sector; the wage premium of the state sector in comparison with the non-state sector increased significantly; and changes in the wage structure of the labour market caused the rise in urban wage inequality
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