Examination of the transition of cultured neuronal cells from submerged to exposed using an environmental scanning electron microscope (ESEM)

Relatively few studies of fully hydrated live or fixed cultured animal cells viewed by environmental scanning electron microscopy (ESEM) have been published. In some cases there may have been some drying out of the cells. In this study the interface between water and cells is imaged as water is carefully evaporated to expose cells. Technical difficulties associated with the process, including inadvertent rewetting of cells are described. Suggestions are made for optimising operating parameters for viewing fully hydrated cultured cells by ESEM. The prospects for viewing live cultured cells are discussed.     

Modeling of cellular pearl chain formation using a double photoconductive layer biochip

A typical double photoconductive layer biochip focusing biological cells and forming specific pearl chains has been studied theoretically in this paper. It was composed of two photoconductive layers coated on the bottom and top of ITO-based glass. A light pattern was used to create face-to-face virtual electrodes and the resulting oscillatory spatial electric field was employed to induce the motion of polarizable neutral particles. In order to estimate the behaviors of the suspended particles, a numerical model including dielectrophoretic forces, dipole–dipole forces and other forces, was implemented by means of the Monte Carlo method. The results indicated that steady-state chains could be formed in a uniform electric field owing to the dipole moment effect. In a non-uniform electric field created by the use of a light pattern, the positive DEP force created a more focused pattern of chains. The work concerning the numerical simulation indicated that this chip could form fixed-length particle chains in perpendicular alignment to satisfy the structured assembly of tissues in the histological engineering application.     

具有比例时滞的细胞神经网络的全局稳定性分析

研究了具有比例时滞的细胞神经网络的平衡点的全局稳定性。通过建立李亚普诺夫函数，得到全局渐进稳定的充分条件。     

Subword complexity of the Fibonacci–Thue–Morse sequence: The proof of Dekking’s conjecture

Recently F. M. Dekking conjectured the form of the subword complexity function for the Fibonacci–Thue–Morse sequence. In this note we prove his conjecture by purely computational means, using the free software Walnut.     

乙二醛诱导细胞凋亡的近红外表面增强拉曼光谱

将60 nm金纳米粒子导入到活的人骨肉瘤细胞中, 用近红外表面增强拉曼散射(SERS)技术获取细胞内化学成分的高分辨SERS信息. 对正常活性细胞和乙二醛诱导的凋亡细胞的比较研究表明, 对于正常活性的细胞, 金纳米探针主要分布在细胞质内(围绕细胞核), 而凋亡细胞内的金纳米探针的分布较为均匀, 在遍布凋亡细胞内的各个位置包括细胞表面均容易找到DNA片段的信息.     

Engineering Hierarchical Recognition-Mediated Senolytics for Reliable Regulation of Cellular Senescence and Anti-Atherosclerosis Therapy

Precise regulation of vascular senescence represents a far-reaching strategy to combat age-related diseases. However, the high heterogeneity of senescence, alongside the lack of targeting and potent senolytics, makes it very challenging. Here we report a molecular design to tackle this challenge through multidimensional, hierarchical recognition of three hallmarks commonly shared among senescence, namely, aptamer-mediated recognition of a membrane marker for active cell targeting, a self-immolative linker responsive to lysosomal enzymes for switchable drug release, and a compound against antiapoptotic signaling for clearance. Such senolytic can target and trigger severe cell apoptosis in broad-spectrum senescent endothelial cells, and importantly, distinguish them from the quiescent state. Its potential for in vivo treatment of vascular diseases is successfully illustrated in a model of atherosclerosis, with effective suppression of the plaque progression yet negligible side effects.     

Influence of emulsification process on structure–properties relationship of highly concentrated reverse emulsion-derived materials

Water-in-Oil high internal phase emulsions (HIPEs) whose continuous phase is polymerizable gave access to highly porous polymeric materials (polyHIPEs). These emulsions were prepared with a laboratory-made homogenizer whose shear frequency and time could be varied to study the influence of the emulsification conditions on the polyHIPEs morphology. Intensive and/or long shear induced a reduction of the cell and connection diameters without any modification of the material global porosity. The mechanical properties were evaluated by estimating the Young’s modulus from compression tests. The mechanical behavior was analogous for all materials possessing a characteristic polyHIPE structure, even if cell sizes were different between samples.     

补阳还五汤联合依达拉奉对脑缺血再灌注损伤后神经细胞凋亡的影响

目的研究补阳还五汤联合依达拉奉对小鼠脑缺血再灌注损伤后神经细胞凋亡及Bcl-2、Bax和Caspase-3表达的影响。方法将50只小鼠随机分为假手术组、模型组、补阳还五汤组、依达拉奉组和两药联用组,每组10只,其中缺血再灌注后1d和7d各5只。首先制备小鼠大脑中动脉缺血模型,TUNEL法观察神经细胞凋亡指数（AI）,免疫组化法观察小鼠大脑皮质神经元Bcl、Bax-2和Caspase-3表达阳性细胞数。结果与模型组比较,补阳还五汤组、依达拉奉组、两药联用组小鼠脑神经细胞AI值均明显降低（P＜0.05）,Bcl-2/Bax比值明显升高（P＜0.05）,Caspase-3表达阳性细胞数明显减少（P＜0.05）,其中又以两药联用组更为明显（P＜0.05）。结论两药联用能降低脑缺血再灌注损伤后神经细胞的凋亡,降低促凋亡基因Caspase-3的表达,协同发挥脑保护作用。     

Regular expression constrained sequence alignment

We introduce regular expression constrained sequence alignment as the problem of finding the maximum alignment score between given strings $S_1$ and $S_2$ over all alignments such that in these alignments there exists a segment where some substring $s_1$ of $S_1$ is aligned to some substring $s_2$ of $S_2$, and both $s_1$ and $s_2$ match a given regular expression R, i.e. $s_1,s_2\in L(R)$ where $L(R)$ is the regular language described by R. For complexity results we assume, without loss of generality, that $n=|S_1|⩾|m|=|S_2|$. A motivation for the problem is that protein sequences can be aligned in a way that known motifs guide the alignments. We present an $\mathrm{O}(nmr)$ time algorithm for the regular expression constrained sequence alignment problem where $r=\mathrm{O}(t^4)$, and t is the number of states of a nondeterministic finite automaton N that accepts $L(R)$. We use in our algorithm a nondeterministic weighted finite automaton M that we construct from N. M has $\mathrm{O}(t^2)$ states where the transition-weights are obtained from the given costs of edit operations, and state-weights correspond to optimum alignment scores we compute using the underlying dynamic programming solution for sequence alignment. If we are given a deterministic finite automaton D accepting $L(R)$ with $t_d$ states then our construction creates a deterministic finite automaton $M_d$ with $t_d^2$ states. In this case, our algorithm takes $\mathrm{O}(t_d^{2}nm)$ time. Using $M_d$ results in faster computation than using M when $t_d<t^2$. If we only want to compute the optimum score, the space required by our algorithm is $\mathrm{O}(t^{2}n)$ ($\mathrm{O}(t_d^{2}m)$ if we use a given $M_d$). If we also want to compute an optimal alignment then our algorithm uses $\mathrm{O}(t^{2}m+t^2|s_1||s_2|)$ space ($\mathrm{O}(t_d^{2}m+t_d^2|s_1||s_2|)$ space if we use a given $M_d$) where $s_1$ and $s_2$ are substrings of $S_1$ and $S_2$, respectively, $s_1,s_2\in L(R)$, and $s_1$ and $s_2$ are aligned together in the optimal alignment that we construct. We also show that our method generalizes for the case of the problem with affine gap penalties, and for finding optimal regular expression constrained local sequence alignments.