Effect of gold nanoparticles on adipogenic differentiation of human mesenchymal stem cells

Gold nanoparticles are very attractive for biomedical products. However, there is a serious lack of information concerning the biological activity of nanosized gold in human tissue cells. An influence of nanoparticles on stem cells might lead to unforeseen consequences to organ and tissue functions as long as all cells arising from the initial stem cell might be subsequently damaged. Therefore the effect of negatively charged gold nanoparticles (9 and 95 nm), which are certified as reference material for preclinical biomedical research, on the adipogenic differentiation of human mesenchymal stem cells (hMSCs) is investigated here. Bone marrow hMSCs are chosen as differentiation model since bone marrow hMSCs are well characterized and their differentiation into the adipogenic lineage shows clear and easily detectable differentiation. In this study effects of gold nanoparticles on adipogenic differentiation are analyzed regarding fat storage and mitochondrial activity after different exposure times (4–21 days). Using time lapse microscopy the differentiation progress under chronically gold nanoparticle treatment is continuously investigated. In this preliminary study, chronically treatment of adipogenic differentiating hMSCs with gold nanoparticles resulted in a reduced number and size of lipid vacuoles and reduced mitochondrial activity depending on the applied concentration and the surface charge of the particles.     

On the Nature of Functional Differentiation: The Role of Self-Organization with Constraints

The focus of this article is the self-organization of neural systems under constraints. In 2016, we proposed a theory for self-organization with constraints to clarify the neural mechanism of functional differentiation. As a typical application of the theory, we developed evolutionary reservoir computers that exhibit functional differentiation of neurons. Regarding the self-organized structure of neural systems, Warren McCulloch described the neural networks of the brain as being “heterarchical”, rather than hierarchical, in structure. Unlike the fixed boundary conditions in conventional self-organization theory, where stationary phenomena are the target for study, the neural networks of the brain change their functional structure via synaptic learning and neural differentiation to exhibit specific functions, thereby adapting to nonstationary environmental changes. Thus, the neural network structure is altered dynamically among possible network structures. We refer to such changes as a dynamic heterarchy. Through the dynamic changes of the network structure under constraints, such as physical, chemical, and informational factors, which act on the whole system, neural systems realize functional differentiation or functional parcellation. Based on the computation results of our model for functional differentiation, we propose hypotheses on the neuronal mechanism of functional differentiation. Finally, using the Kolmogorov–Arnold–Sprecher superposition theorem, which can be realized by a layered deep neural network, we propose a possible scenario of functional (including cell) differentiation.     

An Optical Differentiator Based on a Three-Layer Structure with a W-Shaped Refractive Index Profile

An optical differentiator based on a three-layer resonant structure with a W-shaped refractive index profile is proposed. The differentiation operation is performed in reflection and is associated with the resonant excitation of an eigenmode of the structure localized in the central layer. The presented results of numerical simulations demonstrate the possibility of spatial differentiation of the transverse profile of an incident optical beam, temporal differentiation of the envelope of an incident optical beam, and simultaneous spatial and temporal differentiation with a high quality. The proposed structure can find applications in designing analog optical computing and optical information processing systems.     

X射线辐射与模拟微重力对K562细胞红系分化的联合效应及机制研究

使用氯化高铁血红素(hemin)诱导K562细胞分化作为红系分化模型,并对其进行X射线辐照及地面模拟微重力效应处理,研究辐照、微重力及二者的复合效应对红系分化的影响及机制.X射线辐照及模拟微重力效应处理后的联苯胺染色阳性率及CD235a蛋白表达均下调,细胞增殖抑制、细胞凋亡率及坏死率均增高,红系相关转录因子EPOR及G...     

Monodispersed Bioactive Glass Nanoparticles Enhance the Osteogenic Differentiation of Adipose‐Derived Stem Cells through Activating TGF‐Beta/Smad3 Signaling Pathway

It is important to understand the interaction mechanisms between nanomaterials and adipose‐derived stem cells for biomedical application. Nanoscale bioactive glass has positive effects on guiding osteoblasts differentiation and bone regeneration. However, the effects and molecular mechanism of monodispersed bioactive glass nanoparticles on the osteogenic differentiation of adipose‐derived stem cells are still not clear up to now. In this study, the effects and underlying molecular mechanism of monodispersed bioactive glass nanoparticles on the osteogenic differentiation of adipose‐derived stem cells are investigated in minute detail. The results show that nanoparticles (100–200 nm) can be absorbed by stem cells and is distributed in cytoplasm and nucleus. In both culture conditions (normal and osteoinductive), nanoparticles (80 µg mL⁻¹) can significantly enhance the osteogenic differentiation of stem cells through upregulating the alkaline phosphatase activity, osteogenic genes and protein expressions, as well as calcium deposition. Further study suggests that the activation of transforming growth factor‐beta/Smad3 signaling pathway plays an important role in the osteogenic differentiation of adipose‐derived stem cells enhanced by monodispersed nanoparticles. This study may have important implications for better understanding of stem cells fate induced by monodispersed nanoparticles and provide a promising approach toward stem cells‐based bone regeneration.     

Optical time-domain differentiation based on intensive differential group delay

An optical time-domain differentiation scheme is proposed and demonstrated based on the intensive differential group delay in a high birefringence fibre waveguide. Results show that the differentiation waveforms agree well with the mathematically calculated derivatives. Both error and efficiency will increase when the birefringence fibre becomes longer, and the error rises up more quickly while the efficiency approaches to a maximum of ～0.25. By using a 1-m birefringence fibre a lower error of ～0.26% is obtained with an efficiency of 1% for the first-order differentiation of 10-ps Gaussian optical pulses, and the high-order optical differentiation up to 4th order is achieved with an error less than 3%. Due to its compact structure being easy to integrate and cascade into photonic circuits, our scheme has great potential for ultrafast signal processing.     

傅里叶变换红外光谱法研究HL-60细胞的分化过程

利用傅里叶变换红外光谱法(FTIR)研究了人白血病细胞HL-60在全反式维甲酸(ATRA)作用下向粒细胞分化的过程。结果表明,分化后的HL-60细胞FTIR图谱发生了显著变化,体现在与蛋白质、脂类、核酸和多糖等生物大分子相关的特征性谱带上。细胞内脂类物质烃链增长,含量增加。指纹图谱区域(900～1 300 cm-1)的谱带随着分化进程呈现规律性的变化。其中,核酸含量相对增加,并在1 052和1 153 cm-1附近出现了新的谱峰,二阶导数谱进一步发现在1 022 cm-1处出现新峰,这说明蛋白糖基化,磷酸化以及核酸氢键加强作用在HL-60细胞分化的过程中起着重要作用。通过计算一些图谱参数,并与硝基四唑氮蓝(NBT)还原实验相比较,证明红外图谱的变化与分化程度成正相关。     

耦合环形腔马赫-曾德尔干涉仪瞬态响应及应用

对耦合环形腔马赫-曾德尔干涉仪光脉冲瞬态响应进行了理论和数值研究.利用光束追迹法推导了脉冲传输的解析关系,并数值模拟了传输光场随时间的演化.输出脉冲形状可通过控制损耗进行调解,响应速度为皮秒量级.由于马赫-曾德尔干涉仪两输出端口的互补性,在输出端可同时实现光脉冲微分和积分操作.利用损耗控制机制,可实现单通道脉冲微分和积分操作转换.引入增益补偿损耗,可实现脉冲压缩及产生可调单一触发光脉冲.     

Cell differentiation modeled via a coupled two-switch regulatory network

Mesenchymal stem cells can give rise to bone and other tissue cells, but their differentiation still escapes full control. In this paper we address this issue by mathematical modeling. We present a model for a genetic switch determining the cell fate of progenitor cells which can differentiate into osteoblasts (bone cells) or chondrocytes (cartilage cells). The model consists of two switch mechanisms and reproduces the experimentally observed three stable equilibrium states: a progenitor, an osteogenic, and a chondrogenic state. Conventionally, the loss of an intermediate (progenitor) state and the entailed attraction to one of two opposite (differentiated) states is modeled as a result of changing parameters. In our model in contrast, we achieve this by distributing the differentiation process to two functional switch parts acting in concert: one triggering differentiation and the other determining cell fate. Via stability and bifurcation analysis, we investigate the effects of biochemical stimuli associated with different system inputs. We employ our model to generate differentiation scenarios on the single cell as well as on the cell population level. The single cell scenarios allow to reconstruct the switching upon extrinsic signals, whereas the cell population scenarios provide a framework to identify the impact of intrinsic properties and the limiting factors for successful differentiation.     

基于光学小波微分预处理的联合变换相关目标识别

提出了一种基于光学小波变换微分预处理的光电混合联合变换相关系统,该系统利用同一光路可实时实现对输入图象的小波变换微分预处理和联合变换相关识别.实验结果表明:该系统能得到很尖锐的互相关峰,可显著提高联合变换相关器的识别能力.     

All-optical differentiator based on cross-gain modulation in semiconductor optical amplifier

A novel scheme for carrying out all-optical intensity differentiation is proposed and demonstrated based on the cross-gain modulation (XGM) in a semiconductor optical amplifier (SOA). Because of the XGM, the mathematical definition of differentiation can be expressed by the combined power of the amplified pump pulse and the delayed modulated probe pulse at the output of the SOA. The final waveform and error evolution versus relative time delay between two pulses is investigated. Interestingly enough, it is shown that the acquisition of good differentiation is possible under zero time delay. A further study of zero time delay has been performed for various data rates and shows that the carrier recovery time of the SOA is a speed-limiting factor of the scheme.     

肿瘤细胞诱导分化剂HMBA对自旋标记物TEMPO与蛋白质结合的影响及其意义(英文)

在将TEMPO掺入肿瘤细胞用以研究化学诱导分化剂六亚甲基二乙酰胺（HMBA）诱导分化机理的实验中，观察到一种强的单峰波谱，TEMPO掺入到了蛋白质分子的内部可能形成了局部的高浓度．肿瘤细胞诱导分化剂HMBA在诱导浓度范围内可使一些蛋白质分子的构象发生变化，改变TEMPO与蛋白质分子的结合．因此，HMBA在诱导肿瘤细胞分化的过程中，一定对一些蛋白质分子有直接的作用．     

合成孔径雷达图像反演海面风向新方法的研究

提出了利用基于Tikhonov正则化的二维数值微分方法来反演合成孔径雷达图像海面风向的新方法. 首先将高分辨率合成孔径雷达图像去噪、降采样并分割成数个子图像,利用基于Tikhonov正则化的二维数值微分方法求解所关注子图像每一个点的梯度方向,在此基础上通过带有距离权重的目标函数确定子图像整体强度的梯度方向,该梯度的垂线方向就是所要求解的风向,然后进行模拟试验,在添加误差为10%的随机扰动情况下,分别基于Tikhonov正则化的二维数值微分方法与基于有限差分的Sobel算子方法来反演风向,结果表明,前者误差为0.7293°,后者误差为13.5069°,最后进行了实例试验,结果显示,Sobel算子方法的部分风向反演结果偏离整体风向明显,而基于Tikhonov正则化的二维数值微分方法的风向反演结果一致性较好. 将三个船舶报风向与相应位置合成孔径雷达图像的海面风向反演结果进行对比,Sobel算子方法的风向反演结果平均误差在9.0331°,而基于Tikhonov正则化的二维数值微分方法的风向反演结果平均误差仅为1.1148°. 关键词： 合成孔径雷达 海面风向 数值微分 Sobel算子     

Ultrafast all-optical first- and higher-order differentiators based on interferometers

We demonstrate that a conventional two-arm interferometer can implement first-order temporal differentiation of ultrafast arbitrary optical waveforms. Straightforward extension of this technique to nth-order optical differentiation is also suggested. This approach is experimentally demonstrated by an efficient and accurate first- and second-order temporal differentiation of (sub-)picosecond Gaussian optical pulses.     

图像深度估计的光学微分方法

讨论了光学微分方法在图像深度估计问题中的应用。基于线性成像理论对Farid提出的光学微分模型进行了推广,即用于图像深度估计的两幅图像在成像过程中可以满足任意阶的线性微分关系。此模型拓宽了光学微分的概念,使两次成像之间关系有了更多的光学微分形式。围绕如何选择合适的光学微分关系以使系统的整体性能达到最优,分析了光学成像系统的参量对于图像深度估计的精度以及纵向分辨力的影响,并且对光学微分方法中的关键光学元件—光学掩模板的构建方法及优化问题也作了初步的探讨。     

Surface and inner cell behaviour along skeletal muscle cell in vitro differentiation

During muscle tissue differentiation, in particular in the formation of myotubes from the myoblasts, plasma membrane changes its morpho-functional characteristics. In this study, muscle cell membrane behaviour has been studied along the differentiation of C2C12, a mouse myoblastic adherent cell line. Flat undifferentiated cells, cultured for 3-4 days in the differentiation medium, progressively become thick, long and multinucleated myotubes covered with microvilli. They lose stress fibers and adhesion to the underlying substrate evidentiating an actin redistribution, followed by the spatial organization of thick and thin myofilaments. Sarcomeres and myofibrils occasionally appear, even if a certain percentage of "myosacs" containing randomly oriented filaments can be identified all along the differentiation. M-cadherin, a molecule involved in cell-cell adhesion, also appears in the early differentiation stage, during myoblast fusion. Occasional focal contractions can also be observed in myotubes, which prompt an electrophysiological membrane analysis. When studied by means of patch clamp technique, resting membrane potential appears to undergo a transient depolarization, while input resistance increases until day 5 after differentiation induction, then successively decreases. Capacitance declines until day 5, later appearing enhanced. Moreover, with the induction of differentiation, the pattern of functional voltage-dependent ion channels changes. Therefore, during myogenesis, cell maturation is coupled with changes in cell membrane morphological features and functional characteristics.     

Temporal differentiation of optical signals using resonant gratings

We study theoretically the possibility of performing temporal differentiation of optical signals using a resonant diffraction grating. We demonstrate that the resonant grating allows the calculation of the first-order derivative of an optical signal envelope in the vicinity of waveguide resonant frequencies in the zeroth transmitted diffraction order. The grating is shown to allow the calculation of the fractional derivative of order 1/2 in the vicinity of Rayleigh-Wood anomalies. Numerical simulations based on the rigorous coupled-wave analysis of Maxwell's equations demonstrate the high-quality differentiation of optical signals with temporal features in the picosecond range.     

The Technique of Covariant Differentiation of Retarded Potentials

It is known from scientific literature and courses that various methods of differentiation of expressions retarded in time are used for obtaining electromagnetic fields generated by an arbitrary moving charge. The most common of them is a direct differentiation of the Lienard–Wiechert potentials. However, the method of differentiation of retarded potentials under integral sign is also in wide use. To this end, a special Heaviside–Feynman formalism was developed. In this paper, the interrelation between the foregoing methods is shown. The authors develop the technique of a direct synchronous covariant differentiation of the Lienard–Wiechert potentials and discuss the advantages of this direction.     

Modeling of electronic density of states for single-wall carbon and boron nitride nanotubes

The electronic density of states is calculated for all possible geometric configurations of single-wall carbon and boron nitride nanotubes. The calculation is based on the numerical differentiation of the two-dimensional dispersion relations for graphite and hexagonal boron nitride. The differentiation is performed for all allowed values of the wave vector using the π-electron approximation. For the particular carbon nanotubes chosen as examples, a good agreement is demonstrated between the calculated values of energy spacing of the symmetric van Hove singularities in the density of states and the experimental data obtained from the resonance Raman scattering study.     

Plasticity of human dental pulp stromal cells with bioengineering platforms: A versatile tool for regenerative medicine

In recent years, human dental pulp stromal cells (DPSCs) have received growing attention due to their characteristics in common with other mesenchymal stem cells, in addition to the ease with which they can be harvested. In this study, we demonstrated that the isolation of DPSCs from third molar teeth of healthy individuals allowed the recovery of dental mesenchymal stem cells that showed self-renewal and multipotent differentiation capability. DPSCs resulted positive for CD73, CD90, CD105, STRO-1, negative for CD34, CD45, CD14 and were able to differentiate into osteogenic and chondrogenic cells. We also assayed the angiogenic potential of DPSCs, their capillary tube-like formation was assessed using an in vitro angiogenesis assay and the uptake of acetylated low-density lipoprotein was measured as a marker of endothelial function. Based on these results, DPSCs were capable of differentiating into cells with phenotypic and functional features of endothelial cells. Furthermore, this study investigated the growth and differentiation of human DPSCs under a variety of bioengineering platforms, such as low frequency ultrasounds, tissue engineering and nanomaterials. DPSCs showed an enhanced chondrogenic differentiation under ultrasound application. Moreover, DPSCs were tested on different scaffolds, poly(vinyl alcohol)/gelatin (PVA/G) sponges and human plasma clots. We showed that both PVA/G and human plasma clot are suitable scaffolds for adhesion, growth and differentiation of DPSCs toward osteoblastic lineages. Finally, we evaluated the interactions of DPSCs with a novel class of nanomaterials, namely boron nitride nanotubes (BNNTs). From our investigation, DPSCs have appeared as a highly versatile cellular tool to be employed in regenerative medicine.