磁压榨直肠阴道瘘闭合修补装置的改良设计

目的对本研究团队之前设计的用于磁压榨直肠阴道瘘闭合修补装置进行改良设计。方法分析原有磁压榨直肠阴道瘘闭合修补装置的缺陷,提出了针孔固定的结构方案,并设计了用于磁压榨直肠阴道瘘闭合修补的磁吻合钳。结果针孔结构的设计能够有效防止磁体滑脱,磁吻合钳的孔杆结构能够对吻合磁体起到固定作用,并且有利于吻合磁体的放置。结论磁压榨直肠阴道瘘闭合修补装置的改良设计方案可行,有利于吻合操作。

Linear fast shutdown technology based on self-resonant constant voltage clamping

Transient electromagnetic method(TEM)has been widely used in the field of medium and shallow underground detection due to its high detection efficiency and large detection depth.However,due to the long turn-off time of the transmitting current caused by the inductive characteristics of the transmitting coil,the early signals will be overwhelmed by primary field.Since the early signals contain most of shallow geological signals,it is necessary to reduce the long turn-off time to get shallow layer signal.Due to lack of a reliable and effective clamping method for high-power transmission at present,we design a TEM transmitter fast turn-off circuit,combining self-resonant zero-voltage switching technology with the corresponding timing control circuit to solve this problem effectively.A transient electromagnetic transmitter based on self-resonant constant voltage clamping technology was fabricated to charge the clamping capacitor.The rated transmitting current of the transmitter is 20 A,and the turn-off time is continuously adjustable from 550-50μs.Moreover,the current drop process is approximately linear rather than exponential attenuation.Compared with the existing clamping methods,the proposed clamping method solves the problems that transient voltage suppressor(TVS)clamping cannot be used in high-power occasions and has a high failure rate.It also solves the problem of long pre-charge time in traditional capacitor clamping methods due to insufficient inductance of the small size transmitting coil.The proposed method can provide a reference for fast shutdown of large current.

Characteristics of Transient Outward Potassium Channel Exposed to 3 mT Static Magnetic Field

Acutely isolated mouse hippocampal CA3 pyramidal neurons were exposed to 3 mT static magnetic field,and the characteristics of transient outward K+ channel were studied using the whole-cell patch-clamp technique.The experiment revealed that the amplitude of transient outward potassium channel current was reduced.The maximum activated current densities of control group and exposure group were 163.62±20.68 pA/pF and 98.74±16.57 pA/pF(n=12,P<0.01) respectively.The static magnetic field exposure affected the activation and inactivation process of transient outward potassium channel current.Due to the magnetic field exposure,the half-activation voltage of the activation curves changed from 5.59±1.96 mV to 27.87±7.24 mV(n=12,P<0.05) ,and the slope factor changed from 19.43±2.11 mV to 25.87±4.22 mV(n=12,P<0.05) .The half-inactivation voltage of the inactivation curves also changed from-56.09±0.89 mV to-57.16±1.10 mV(n=12,P>0.05) and the slope factor of the inactivation curves from 8.69±0.80 mV to 10.87±1.02 mV(n=12,P<0.05) .The results show that the static magnetic field can change the characteristics of transient outward K+ channel,and affect the physiological functions of neurons.

Single molecule DNA compaction by purified histones

单个 DNA 分子由的压缩净化嘘用磁性的镊子被学习。当时，压缩率很快增加 hist 一集中从 0.002 ～ 0.2 mmol/L 被增加，并且当集中在 0.2 mmol/L 以外时，浸透。压缩的时间功课是指数的在低嘘一集中。它在高集中成为 sigmoidal。在绑了在 DNA 的 hist 之间的 Cooperativity 被建议为转变负责。hist 在低集中随机被装载到 DNA 上。因为 DNA 的结构的扭转由界限导致了，他们趋于在高集中合作地绑 DNA 嘘变得重叠以便一个的绑定嘘一个人便于其它的绑定。在很大的力量下面，压缩 histone-DNA 建筑群能与一种步尺寸以一种分离方式被破坏类似于 60 nm。但是不能是的 hist 完全剥去 DNA，被 histone 固定的 DNA 的降低的 B-S 转变高原揭示。