A neglected GABAergic astrocyte: Calcium dynamics and involvement in seizure activity

Gamma-aminobutyric acid (GABA) contributes substantially to neurocognitive function as an important inhibitory neurotransmitter in the human cerebral cortex. However, the pathophysiology of disorders such as epilepsy are not well understood, since GABA agonists are not quite effective in treating epilepsy. Knowledge of the mechanism of action of GABA would contribute to review previously proposed anti-epileptic processes by GABA agonists. In this study based on recent experiments on GABAergic astrocytes, we developed a modified GABAergic astrocyte model, and successfully simulated a long-lasting Ca²⁺ oscillation in astrocytes after 0.5-s stimulation of GABAergic transmission. We then incorporated this GABAergic astrocyte model into a classical Ullah-Schiff seizure model and surprisingly found that this GABAergic astrocyte model functions to hinder the anti-epileptic action of GABA agonists, thereby explaining their low efficiency in previous experiments. These results also update our knowledge of the mechanism of action of GABA and the effects of astrocytes on physiological and pathological functions of the brain.     

Characteristics of scalded dough fermented by co-cultures of Saccharomyces cerevisiae Y10, Wickerhamomyces anomalus Y13 and Torulaspora delbrueckii Y22

Scalding process could change properties of dough. Co-culture of yeasts could improve the quality of product. In this study, characteristics of scalded dough with co-cultures of Saccharomyces cerevisiae Y10, Wickerhamomyces anomalus Y13 and Torulaspora delbrueckii Y22 were investigated. Most starch granules lost shape and crystal pattern after scalding, meanwhile, gluten network had become weak, suggesting the gelatinisation of starch and damage of gluten protein. After fermentation, Y13 and Y22 cell populations increased rapidly. However, the cell number of Y10 decreased from 6.91 Lg CFU per gram dough to 5.42 Lg CFU per gram dough. Gluten protein aggregated into chunks after 8 h of fermentation, meanwhile, the water molecules in dough were bound more tightly. These results indicated that scalded dough provide a unique environment for the growth of yeasts, and further affect the characteristics of dough during fermentation.     

Propagation properties of foreshock cavitons: Cluster observations

Foreshock cavitons are transient phenomena observed in the terrestrial foreshock region. They are characterized by a simultaneous depression of magnetic field magnitude and plasma density, which are bounded with enhancements of these two parameters and surrounded by ultralow frequency(ULF) waves. Previous studies focused on the interplanetary magnetic field(IMF) conditions, solar wind(SW) conditions, and the growth of the foreshock waves related to the generation of foreshock cavitons. Previously, a multipoint spacecraft analysis method using Cluster data was applied to analyze only two foreshock cavitons, and this method did not consider uncertainties. In this study, multipoint spacecraft analysis methods, including the timing method, the minimum directional derivative(MDD) method, and the spatiotemporal difference(STD) method are applied to determine the velocity in both spacecraft and solar wind frames. The propagation properties show good agreement with previous results from simulations and observations that most cavitons move sunward in the solar wind frame, with the velocities larger than the Alfvén speed. The propagation properties of foreshock cavitons support the formation mechanism of cavitons in previous simulations, which suggested that cavitons are formed due to the nonlinear evolution of compressive ULF waves. We find that there is clear decreasing trend between the size of cavitons and their velocity in the solar wind frame. In addition, the timing method considering errors has been applied to study the evolution properties by comparing the velocities with errors of the leading and trailing edges, and we identify three stable cavitons and one contracting caviton, which has not been studied before.Most cavitons should remain stable when they travel toward the Earth's bow shock. The relationship between the size of foreshock cavitons and their distance from the bow shock is also discussed.     

Co-effect of Mechanical Ball-milling and Microenvironmental Polarity on Morphology and Properties of Nanocellulose

Cellulose is a linear polymer consisting of D-anhydroglucose units joined by β-1,4-glycosidic linkages. The densely packed cellulose molecular chain forms crystalline cellulose through strong hydrogen bonding. Owing to its chemical tunability and excellent mechanical resistance, nanocellulose is widely used in everyday life and the industrial sector. In this work, cellulose materials were nanoprocessed by mechanical ball-milling(1) in polar solvents(N,N-dimethylformamide or dimethyl sulfoxide) with esterification or(2) in hydrophobic agents(polydimethylsiloxane or polytetrafluoroethylene) with different molecular weights. Cellulose nanofibers and nanosheets with different hydrophilic and hydrophobic properties were obtained, and the mechanism of cellulose disintegration along a crystallographic plane induced by mechanical force and the polarity condition were discussed. This work affords a new way to manipulate the morphology and properties of nanocellulose.     

基于Libsvm的304不锈钢人工缺陷弱磁信号反演研究

针对304奥氏体不锈钢顺磁性材料,提出了将多类分类支持向量机Libsvm算法用于弱磁信号磁异常反演的研究.采用正交试验设计,制作4块304奥氏体不锈钢试块,共16组人工槽缺陷并使用弱磁检测对试块进行检测.对采集到的缺陷信号磁异常提取占宽、幅值、面积等特征值,使用Libsvm算法建立缺陷信号磁异常与缺陷之间的联系,并测试...     

A robust polyacrylic acid/chitosan cryogel for rapid hemostasis

Science China Technological Sciences - Currently, it is a challenge to develop hemostatic materials with high water absorption capacity and anti-fatigue properties for quickly preventing massive...