Astrocyte and ions metabolism during epileptogenesis:A review for modeling studies

As a large group of cells in a central nervous system, astrocytes have a great influence on ion and energy metabolism in a nervous system. Disorders of neuronal ion and energy metabolism caused by impaired astrocytes play a key role in the pathogenesis of epilepsy. This paper reviews the existing computational models of epileptogenesis resulting from impaired astrocytes and presents several open perspectives with regard to ion and energy metabolism-induced epileptogenesis in a neuron-astrocyte-capillary coupled model.     

镶嵌钨硅酸的新型有机-无机纳米复合薄膜的制备及光致变色性能研究

将超分子自组装技术与Sol-gel过程相结合,制备了镶嵌Keggin结构钨硅酸的MAAM/VTEOS/TEOS纳米复合薄膜,并采用IR,XRD和TG-DSC等方法对薄膜进行了结构表征.在复合薄膜光照变蓝后,通过UV-Vis和ESR光谱对薄膜的光致变色性能及其机理进行了研究.结果表明,钨硅酸在复合网络中仍保持Keggin结构,与有机-无机复合基体中的-NH₂通过氢键发生强烈的相互作用,经紫外光照后发生电荷转移,[SiW₁₂O₄0]₄^-被还原为[SiW₁₂O₄0]₅^-,同时产生氨基自由基.褪色过程则与氧气存在与否有关,实验结果表明,该薄膜具有良好的光致变色性能,对光有较快的响应恢复速度和良好的可逆重复性.     

Periodic habitat destruction and migration can paradoxically enable sustainable territorial expansion

Nonlinear Dynamics - Despite depleting the resources in their environments, some species and societies are capable of sustainable habitat expansion by alternating between a low-growth migratory...     

W/O微乳液体系稳定条件的研究

研究表明[1～4] ,一个好的微乳液体系要求具有稳定范围宽阔 ,对ｐＨ值和温度的变化不敏感等特点。本文研究目的是为了寻找一个适合制备所需功能氧化物粒子的微乳液体系 ,考察研究Ｔｘ 6～Ｃ4Ｈ9ＯＨ/ｃ Ｃ6Ｈ1 2 /Ｈ2 Ｏ体系Ｗ/Ｏ微乳液在不同条件下能稳定存在的组成范围以及温度和不同ｐＨ值对该稳定组成区域的影响。1　实验部分1 1　实验试剂本实验以Ｔｘ 6(烷基聚氧乙烯酚醚 )为表面活性剂 ,Ｃ4Ｈ9ＯＨ(正丁醇 )为助表面活性剂 ,ｃ Ｃ6Ｈ1 2(环己烷 )为油相。除Ｔｘ 6由上海高桥石化三厂提供外 ,其它试剂均为分析纯。1 2　实验内容在 2…     

Tuning Electron-Withdrawing Strength on Phenothiazine Derivatives: Achieving 100 % Photoluminescence Quantum Yield by NO2 Substitution

The weak fluorescence (quantum yield <1 % in cyclohexane) of phenothiazine ( PTZ ) impedes its further application. In addition, the nitro group (NO₂) is a well-known fluorescence quencher. Interestingly, we obtained a highly fluorescent chromophore by combining these two moieties, forming 3-nitrophenothiazine ( PTZ-NO₂ ). For comparison, a series of PTZ derivatives bearing electron-withdrawing groups (EWGs; CN and CHO) or electron-donating groups (EDGs; OMe) at the 3-position have been designed and synthesized. The phenothiazines bearing EWGs exhibited enhanced emission compared with the parent PTZ or EDG derivatives. Computational approaches unveiled that for PTZ and PTZ-OMe , the transitions are from HOMOs dominated by π orbitals to LUMOs of mixed sulfur nonbonding–π* orbitals, and hence are partially forbidden. In contrast, the EWGs lower the energy level of the lone-pair electrons on the sulfur atom, thereby suppressing the mixing of the nonbonding orbital with the π* orbital in the LUMO, such that the allowed ππ* transition becomes dominant. This work thus demonstrates a judicious chemical design to fine-tune the transition character in PTZ analogues, with PTZ-NO₂ attaining 100 % emission quantum yields in nonpolar solvent.     

Direct determination of chlorophenols in water samples through ultrasound-assisted hollow fiber liquid–liquid–liquid microextraction on-line coupled with high-performance liquid chromatography

In this study we on-line coupled hollow fiber liquid–liquid–liquid microextraction (HF-LLLME), assisted by an ultrasonic probe, with high-performance liquid chromatography (HPLC). In this approach, the target analytes – 2-chlorophenol (2-CP), 3-chlorophenol (3-CP), 2,6-dichlorophenol (2,6-DCP), and 3,4-dichlorophenol (3,4-DCP) – were extracted into a hollow fiber (HF) supported liquid membrane (SLM) and then back-extracted into the acceptor solution in the lumen of the HF. Next, the acceptor solution was withdrawn on-line into the HPLC sample loop connected to the HF and then injected directly into the HPLC system for analysis. We found that the chlorophenols (CPs) could diffuse quickly through two sequential extraction interfaces – the donor phase – SLM and the SLM – acceptor phase – under the assistance of an ultrasonic probe. Ultrasonication provided effective mixing of the extracted boundary layers with the bulk of the sample and it increased the driving forces for mass transfer, thereby enhancing the extraction kinetics and leading to rapid enrichment of the target analytes. We studied the effects of various parameters on the extraction efficiency, viz. the nature of the SLM and acceptor phase, the compositions of the donor and acceptor phases, the fiber length, the stirring rate, the ion strength, the sample temperature, the sonication conditions, and the perfusion flow rate. This on-line extraction method exhibited linearity (r² ≥ 0.998), sensitivity (limits of detection: 0.03–0.05 μg L⁻¹), and precision (RSD% ≤ 4.8), allowing the sensitive, simple, and rapid determination of CPs in aqueous solutions and water samples with a sampling time of just 2 min.     

三维电磁扩散场数值模拟及磁化效应的影响

采用矢量有限元法实现了三维电磁扩散场数值模拟,并成功将其应用在大地电磁的正演研究中.为灵活精确地拟合起伏地形和地下不规则构造,采用由不规则四面体单元组成的非结构化网格,可根据模型设计的需要调整网格的大小.引入了基于二次场理论,将解析的一次场从总场中扣除,直接计算二次场,使得误差仅局限于相对较小的二次场,以提高总场计算精度.常规的节点有限元法不满足电性分界面上法向电场不连续和无源区单元内电流密度无散,违反麦克斯韦方程组.为克服节点有限元法的弊端,使用矢量有限元法求解基于二次电场的偏微分方程.另外,在算法设计中,考虑了磁导率参数的变化,可以模拟磁导率不均匀的模型.通过与COMMEMI模型已发表的结果对比,证明了本文算法的正确性和精确性.为突显非结构网格优势,计算了椭球异常体模型和任意地形模型的MT响应,并详细讨论了地形和磁化效应对三维数值模拟结果的影响.     

三氧化钼/苯胺层状复合材料的制备

以三氧化钼为无机主体, 用十二烷基胺对三氧化钼层间进行改性, 成功地制备了三氧化钼/苯胺层状复合材料. X射线衍射、元素分析、扫描电子显微镜、红外光谱测试及差热分析结果表明, 苯胺分子已成功地插入三氧化钼层间, 所得复合物化学式为[ANI]0.4MoO3. 插层后, 三氧化钼仍保持规则有序的层状结构, 其层间距扩大至1.318 nm. 讨论了无机主体与有机客体之间的相互作用、苯胺在层间的可能排布形式以及苯胺插入层间的反应机理.     

由咪唑-4,5-二羧酸和1,4-对苯二甲酸构筑的一个三维镉(Ⅱ)配位聚合物的合成、结构及荧光性质

以CdCl₂、咪唑-4,5-二羧酸(H₃IDC)和1,4-对苯二甲酸(H₂BDC)为原料,在水热条件下合成得到了一个新的三维镉(Ⅱ)配位聚合物[Cd₂(HIDC)(BDC)(H₂O)]_n(1),通过元素分析、红外光谱、粉末X-射线衍射、热重分析和单晶X-射线衍射法等对其组成和结构进行了表征。单晶X-射线结构分析表明,在配合物1的晶体结构中含有沿a轴方向的一维无限的{[Cd₂(CO₂)]₂(CO₂)₂}_n配位聚合链。此聚合链再通过桥连HIDC²与BDC^2-配体的连接,最终形成一复杂的三维金属-有机框架结构。配合物1的固体室温荧光测试结果表明,在波长为350nm的光激发下于456nm处出现强烈的荧光发射。     

Dynamical response of a neuron–astrocyte coupling system under electromagnetic induction and external stimulation

Previous studies have observed that electromagnetic induction can seriously affect the electrophysiological activity of the nervous system. Considering the role of astrocytes in regulating neural firing, we studied a simple neuron–astrocyte coupled system under electromagnetic induction in response to different types of external stimulation. Both the duration and intensity of the external stimulus can induce different modes of electrical activity in this system, and thus the neuronal firing patterns can be subtly controlled. When the external stimulation ceases, the neuron will continue to fire for a long time and then reset to its resting state. In this study, "delay" is defined as the delayed time from the firing state to the resting state, and it is highly sensitive to changes in the duration or intensity of the external stimulus. Meanwhile, the self-similarity embodied in the aforementioned sensitivity can be quantified by fractal dimension. Moreover, a hysteresis loop of calcium activity in the astrocyte is observed in the specific interval of the external stimulus when the stimulus duration is extended to infinity, since astrocytic calcium or neuron electrical activity in the resting state or during periodic oscillation depends on the initial state. Finally, the regulating effect of electromagnetic induction in this system is considered. It is clarified that the occurrence of "delay" depends purely on the existence of electromagnetic induction. This model can reveal the dynamic characteristics of the neuron–astrocyte coupling system with magnetic induction under external stimulation. These results can provide some insights into the effects of electromagnetic induction and stimulation on neuronal activity.