BMP-4発現制御によるマウスiPS細胞の非神経外胚葉および中胚葉系への分化誘導

要約のみTohoku University江草宏課

Concept-Based Approach in Writing Instruction: The Effect of Concept Model

This paper reports the effect of concept model as mediation in writing instruction. Concept in this study refers to the generalizing language in an argumentative essay (e.g. thesis statement, topic sentence, wrap-up sentence and restatement of thesis) since such language constitutes the basic structure of an essay. Based on Ferreira and Lantolf (2008), a five-week experiment was performed, in which “movement from the abstract to the concrete†approach was used. The experiment procedure consisted of four steps: facing problems, producing concept models, revising concept models and applying concept models. But the control group experienced a traditional approach, “movement from the concrete to the abstractâ€. The results manifest the facilitating effect of concept model on knowledge internalization

Asymptotic behavior of the principal eigenvalue of a linear second order elliptic operator with large advection and general boundary conditions

Consider the eigenvalue problem of a linear second order elliptic operator: \begin{equation} \nonumber -D\Delta \varphi -2\alpha\nabla m(x)\cdot \nabla\varphi+V(x)\varphi=\lambda\varphi\ \ \hbox{ in }\Omega, \end{equation} complemented by the Dirichlet boundary condition or the following general Robin boundary condition: $$\frac{\partial\varphi}{\partial n}+\beta(x)\varphi=0 \ \ \hbox{ on }\partial\Omega,$$ where $\Omega\subset\mathbb{R}^N (N\geq1)$ is a bounded smooth domain, $n(x)$ is the unit exterior normal to $\partial\Omega$ at $x\in\partial\Omega$, $D>0$ and $\alpha>0$ are, respectively, the diffusion and advection coefficients, $m\in C^2(\overline\Omega),\,V\in C(\overline\Omega)$, $\beta\in C(\partial\Omega)$ are given functions, and $\beta$ allows to be positive, sign-changing or negative. In \cite{PZZ2019}, the asymptotic behavior of the principal eigenvalue of the above eigenvalue problem as $D\to0$ or $D\to\infty$ was studied. In this paper, when $N\geq2$, under proper conditions on the advection function $m$, we establish the asymptotic behavior of the principal eigenvalue as $\alpha\to\infty$, and when $N=1$, we obtain a complete characterization for such asymptotic behavior provided $m'$ changes sign at most finitely many times. Our results complement or improve those in \cite{BHN2005,CL2008,PZ2018} and also partially answer some questions raised in \cite{BHN2005}.Comment: 36 pages. Comments are welcom

Boundary regularity of uniformly rotating vortex patch

In this paper we consider the singularities on the boundary of limiting $V$-states of the 2-dim incompressible Euler equation. By setting up a Weiss-type monotoncity formula for a sign-changing unstable elliptic free boundary problem, we obtain the classification of singular points on the free boundary: the boundary of vortical domain would form either a right angle ($90^\circ$) or a cusp ($0^\circ$) near these points in the limiting sense. For the first alternative, we further prove the uniformly regularity of the free boundary near these isolated singular points

Molecular imaging of the bioeffects of β-amyloid and metal ions on live human neuroblastoma cells: internalization, subcellular localization and induction of ROS

Alzheimer’s disease (AD) is a progressive neurodegenerative disease characterized by the deposition of extracellular amyloid-β(Aβ) plaques that are rich in metal ions such as zinc, copper and iron. The neurotoxic role of Aβ has been well established but the mechanism of action is still poorly understood. Recent in vitro evidence suggest that Aβ can interact with metal ions such as Zn(II), Cu(II) or Fe(II/III) which promote its aggregation and/or ROS production. However, it is unclear whether this is the case in cells and whether/how extracellular Aβ can get into cells. Our recently developed molecular imaging probes for iron, copper and ROS enable us to look at this in real time in live cells at subcellular resolution. First, we tagged the Aβ covalently with a fluorescent dye which allows its interactions with cells to be monitored under a microscope. Our laser confocal imaging experiments with human neuroblastoma cells revealed that Aβ accumulated at the cell surface first and subsequently entered the cells via endocytosis pathway over a period of a few hours and finally deposited into endosomes/lysosomes in the cells. The deposition of Aβ induced a marked production of oxygen free radicals in the mitochondria of the cells, as revealed by our oxygen free radical probe and colocalization experiments. Incubation of metal ions such as copper(II) increased the production of oxygen radicals significantly while zinc(II) appears to be protective against ROS production. Our data provided compelling and direct evidence on how amyloid-β(Aβ) entering the cells and its induction of oxygen free radicals as well as the effects of metal ions on the radical production at subcellular level

Experimental demonstration of the criterion for the prepare-and-measure nonlocality

The prepare-and-measure theory is a new type of quantum paradox that reveals the incompatibility between classical theory and quantum mechanics in terms of the dimensionality of physical systems. Just as the Horodecki criterion can determine whether given quantum states are capable of exhibiting Bell nonclassicality, a similar criterion is needed for the prepare-and-measure theory to determine whether given quantum states can exhibit the prepare-and-measure nonclassicality.Recently, Poderini \emph{et al.} [Phys. Rev. Research 2, 043106 (2020)] presented such a criterion for the prepare-and-measure nonclassicality.In this work, we experimentally validate this criterion -- 52 different sets of quantum states are prepared and tested one by one using this criterion to determine whether they can exhibit the prepare-and-measure nonclassicality, and the experimental results are in good agreement with the theoretical expectations. The criterion experimentally verified here has the potential to be widely used in future research on the prepare-and-measure nonclassicality

A Multiscale Data-Driven Stochastic Method for Elliptic PDEs with Random Coefficients

In this paper, we propose a multiscale data-driven stochastic method (MsDSM) to study stochastic partial differential equations (SPDEs) in the multiquery setting. This method combines the advantages of the recently developed multiscale model reduction method [M. L. Ci, T. Y. Hou, and Z. Shi, ESAIM Math. Model. Numer. Anal., 48 (2014), pp. 449--474] and the data-driven stochastic method (DSM) [M. L. Cheng et al., SIAM/ASA J. Uncertain. Quantif., 1 (2013), pp. 452--493]. Our method consists of offline and online stages. In the offline stage, we decompose the harmonic coordinate into a smooth part and a highly oscillatory part so that the smooth part is invertible and the highly oscillatory part is small. Based on the Karhunen--Loève (KL) expansion of the smooth parts and oscillatory parts of the harmonic coordinates, we can derive an effective stochastic equation that can be well-resolved on a coarse grid. We then apply the DSM to the effective stochastic equation to construct a data-driven stochastic basis under which the stochastic solutions enjoy a compact representation for a broad range of forcing functions. In the online stage, we expand the SPDE solution using the data-driven stochastic basis and solve a small number of coupled deterministic partial differential equations (PDEs) to obtain the expansion coefficients. The MsDSM reduces both the stochastic and the physical dimensions of the solution. We have performed complexity analysis which shows that the MsDSM offers considerable savings over not only traditional methods but also DSM in solving multiscale SPDEs. Numerical results are presented to demonstrate the accuracy and efficiency of the proposed method for several multiscale stochastic problems without scale separation