Thalamo-cortical axons regulate the radial dispersion of neocortical GABAergic interneurons

Neocortical GABAergic interneuron migration and thalamo-cortical axon (TCA) pathfinding follow similar trajectories and timing, suggesting they may be interdependent. The mechanisms that regulate the radial dispersion of neocortical interneurons are incompletely understood. Here we report that disruption of TCA innervation, or TCA-derived glutamate, affected the laminar distribution of GABAergic interneurons in mouse neocortex, resulting in abnormal accumulation in deep layers of interneurons that failed to switch from tangential to radial orientation. Expression of the KCC2 cotransporter was elevated in interneurons of denervated cortex, and KCC2 deletion restored normal interneuron lamination in the absence of TCAs. Disruption of interneuron NMDA receptors or pharmacological inhibition of calpain also led to increased KCC2 expression and defective radial dispersion of interneurons. Thus, although TCAs are not required to guide the tangential migration of GABAergic interneurons, they provide crucial signals that restrict interneuron KCC2 levels, allowing coordinated neocortical invasion of TCAs and interneurons.

Research of Operational Characterizations of Cutting Discs with Oriented Abrasive Grains

Efficiency of the polishing process is determined by the properties of abrasive grains, including its form parameter and orientation in the body of the grinding tool. It is possible to improve the operational characterizations of the grinding instruments, in particular – cutting discs, by ordering of the grain geometry, selection of the rational form and orientation of abrasive grains for specific processing conditions and parameters of the power load. For the solution of such problem the developed and patented method for production of grinding tools with the orientated abrasive grains is offered [1]. According to the specified method the cutting discs with radial and tangential orientation of abrasive grains are made. As a comparative standard, discs without orientation of abrasive grains are made also. Comparative tests by cutting according to the scheme of pressing of workpiece to a disc with a constant effort are carried out. It is established that orientation of abrasive grains significantly influences the operational characterizations of cutting discs. So, the cutting ability of cutting discs with radial orientation of abrasive grains is 15-17% higher during processing of various materials, than at standard tools. The grinding coefficient of cutting discs with tangential orientation of abrasive grains is 25-29% higher, than at usual discs with non-oriented grains. Results of an assessment of effective power of cutting in addition confirm that discs with the radial orientation of grains are working with the greatest intensity and at the same time with biggest wear. Further, on decrease, cutting discs with non-oriented grains follow. Instruments with tangential orientation of abrasive grains are characterized by the smallest cutting ability and the smallest wear. Such effect is caused by that the radial focused abrasive grains possess the greatest sizes of forward corners, and tangential focused grains possess the smallest sizes. It is established also that application of cutting discs with radial orientation of abrasive grains in comparison with ordinary tools allows to reduce temperature in a cutting zone by 20-30 °C and to reduce the size of zones of thermal influence.

Stability Analysis of the Center Arch Girder for Special Astronomical Dome

The special astronomical dome is an important instrument in the multi-object space detecting system. With the background of the special astronomical dome, the potential energy equations of center arch girder with displacement and angle as unknown fundamental quantities were established according to energy principle. The critical loading in buckling of the hinged center arch girder under erect orientation and radial orientation loading was calculated in this paper. The results are very valuable for designing the center arch girders of the special dome and solving the mechanical problems of the statically indeterminate arch girders with the similar structure.

Radial Orientation Mechanism and Research of Short Fiber in Extrusion Die

Combining with Jeffery equation and mechanics model of fixed point of Euler rigid body, research was done to study the mechanism and method of the short fiber radial orientation and characteristics of movement in tread extrusion process. The influence of tension flow field and shear flow field in flow channel on short fibers orientation has been systemically analyzed by flow characteristics of the tread during the extrusion process and combining with Jeffery equation and mechanics model of fixed point of Euler rigid body. The result show that the expansion ratio and the expanding angle of cross section are the key factors to determine the radial orientation of short fiber. Mathematical model of short fiber radial orientation was established. The extrusion die, which has a hinder dam by adopting such principle has been designed. The result also show that the best expansion ratio was 3-4, obtaining the average orientation angle between 70o-80o. and the rationality of the radial oriented mechanism and the mathematical model are verified.

Effect of Die Structure on Radial Orientation of Short Fiber in Tire Tread and its Performance

Extrusion and molding is one of the most important manufacturing processes of short fiber-rubber composite material. In order to be used to tire tread, the short fibers in rubber are wanted to be radial orientated. But the orientation of short fibers depends on the die structure, and the performances of short fiber-rubber composite material depend on the radial orientation degree of short fibers. So, the die structure has been studied by experiments in order to get a proper die structure for manufacturing of short fiber-rubber composite material. The experimental results indicate that the proper die structure parameters are: the molding length is 15mm, the molding height is 9mm, the channel length is 75mm, the channel height is 12mm and the channel angle is 135º.

Electric field variability and classifications of Titan's magnetoplasma environment

The atmosphere of Saturn's largest moon Titan is driven by photochemistry, charged particle precipitation from Saturn's upstream magnetosphere, and presumably by the diffusion of the magnetospheric field into the outer ionosphere, amongst other processes. Ion pickup, controlled by the upstream convection electric field, plays a role in the loss of this atmosphere. The interaction of Titan with Saturn's magnetosphere results in the formation of a flow-induced magnetosphere. The upstream magnetoplasma environment of Titan is a complex and highly variable system and significant quasi-periodic modulations of the plasma in this region of Saturn's magnetosphere have been reported. In this paper we quantitatively investigate the effect of these quasi-periodic modulations on the convection electric field at Titan. We show that the electric field can be significantly perturbed away from the nominal radial orientation inferred from Voyager 1 observations, and demonstrate that upstream categorisation schemes must be used with care when undertaking quantitative studies of Titan's magnetospheric interaction, particularly where assumptions regarding the orientation of the convection electric field are made.