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In this paper, the dynamics of phase coarsening at ultrahigh volume fractions (0.9≤VV≤0.96) is first studied based on two-dimensional phase-field simulations by numerically solving the time-dependent Ginzburg–Landau and Cahn–Hilliard equations. It is shown that the cubic average radius of particles is approximately proportional to time that is in good agreement with one of experimental observations. The microstructural evolutions for different ultrahigh volume fractions are shown. The scaled particle size distribution as functions of the dispersoid volume fraction is presented. The interesting finding is that the particle size distribution derived from our simulations at ultrahigh volume fractions is close to Wagner’s particle size distribution due to interface-controlled ripening rather than Hillert’s grain size distribution in grain growth. The changes of shapes of particles are carefully studied with increase in volume fraction. It is found that some liquid-filled triple junctions are formed as a result of particle shape accommodation at ultrahigh volume fraction, VV≈0.96. [ABSTRACT FROM AUTHOR]

The continuous-time random walk (CTRW) model is a useful tool for the description of diffusion in nonequilibrium systems, which is broadly applied in nature and life sciences, e.g., from biophysics to geosciences. In particular, the integro-differential equations for diffusion and diffusion-advection are derived asymptotically from the decoupled CTRW model and a generalized Chapmann-Kolmogorov equation, with generic waiting time probability density function (PDF) and external force. The advantage of the integro-differential equations is that they can be used to investigate the entire diffusion process i.e., covering initial-, intermediate- and long-time ranges of the process. Therefore, this method can distinguish the evolution detail for a system having the same behavior in the long-time limit but with different initial- and intermediate-time behaviors. An integro-differential equation for diffusion-advection is also presented for the description of the subdiffusive and superdiffusive regime. Moreover, the methods of solving the integro-differential equations are developed, and the analytic solutions for PDFs are obtained for the cases of force-free and linear force. [ABSTRACT FROM AUTHOR]

Objective To investigate the alterations of syncytin, a fusogenic membrane protein involved in syncytiotrophoblastic layer formation, and its receptor ASCT2 expression in placental development and pre-eclampsia. Design Analyses of syncytin and ASCT2 expression in placentas from different stages of pregnancy and women with pre-eclampsia and in cytotrophoblasts cultured in normoxic and hypoxic conditions. Setting Placental samples were collected from a tertiary medical centre. Population Sixteen women with pre-eclampsia and 58 pregnant women presented as pregnancy (5–19 weeks of gestation) for elective termination, preterm birth, or normal term delivery. Methods The quantitative real-time polymerase chain reaction was used to study the syncytin and ASCT2 expression during placental development in 35 placentas from women without pre-eclampsia (ranged from 5 to 40 weeks of gestation) and the alterations of pre-eclamptic placentas ( n= 16) compared with gestational-age-matched controls ( n= 16). Western blot analysis was performed to study the protein level of syncytin in pre-eclamptic placentas and gestational-age-matched controls. The hypoxic effect on trophoblastic syncytin and ASCT2 expression was further studied in cytotrophoblasts cultured in 2% oxygen ( n= 7). Main outcome measures Syncytin and ASCT2 messenger RNA (mRNA) in placental tissue and cytotrophoblasts. Results The level of syncytin mRNA expression increased significantly since the first trimester of pregnancy until 37 weeks of gestation, when the level of syncytin expression was reduced. The ASCT2 mRNA expression was decreased significantly since the second trimester and was relatively stable since then to 40 weeks of gestation. Furthermore, a significant reduction in syncytin mRNA expression was observed in pre-eclamptic placentas and cytotrophoblasts cultured in hypoxia, but not a reduction in ASCT2 mRNA expression. Correlatively, the protein level of syncytin was decreased in pre-eclamptic placentas. Conclusions A reduced placental expression of syncytin but not ASCT2 may contribute to altered cytotrophoblastic cell fusion processes and disturbed placental function in pre-eclampsia. Correspondingly, hypoxia decreases syncytin but not ASCT2 gene expression in cultured cytotrophoblasts. [ABSTRACT FROM AUTHOR]

A theory for phase coarsening in multicomponent systems is developed in which both the multicomponent thermodynamic effect and kinetic effect from a nonzero volume fraction are considered. In contrast to previous theory, a diffusion screening zone for a coarsening particle due to nonzero volume fraction is introduced. The evolution equation for phase coarsening in multicomponent systems is derived in a rigorous way in the framework of the maximum rate of dissipation with the constraints of mass and energy conservation. Existing previous relations are recovered and generalized. Some findings such as the relationship between the maximum particle size and volume fraction and particle size distribution in multicomponent systems are discovered. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article on prenatal diagnosis of otocephaly, published in the previous issue.

Summary: Stimulated emission depletion (STED) microscopy performed using continuous‐wave (CW) lasers has been investigated and developed by Willig et al. (Nature Methods, 2007, 4(11):915) for nearly a decade. Kuang et al. (Review of Scientific Instruments, 2010, 81:053709) developed the CW STED microscopy technique with 405 nm excitation and 532 nm depletion beams. In their research, Coumarin 102 dye was adopted and was found to be depletable. In this study, a parametric investigation of the depletion of Coumarin 102 dye is carried out experimentally. The influence of the excitation and depletion beam intensities and dye concentrations on the depletion efficiency are studied in detail. The results indicate the following: (1) The highest depletion occurs for the 100 μM Coumarin 102 solution, with a 1.4 μW excitation beam and a 115.3 mW depletion beam. (2) The minimum saturation intensity ( I s) of STED, that is 13 MW cm–2, is observed when the Coumarin 102 solution concentration is 10 μM. (3) I s values calculated directly from the depletion power derived with the cross‐sectional area due to the full‐width‐at‐half‐maximum (FWHM) of the depletion beam show poor accuracy, where I s may be overestimated. Thus, a correction factor for the cross‐sectional area is proposed. We also find that I s is not exactly constant for a fixed excitation beam power and dye concentration. This trend indicates that the conventional suppression function η ( x ) = e − ln ( 2 ) I STED ( x ) / I s derived from picosecond STED may cause errors in evaluating the depletion process in CW STED microscopy. [ABSTRACT FROM AUTHOR]