Synaptic remodeling in mouse motor cortex after spinal cord injury

Spinal cord injury dramatically blocks information exchange between the central nervous system and the peripheral nervous system.The resulting fate of synapses in the motor cortex has not been well studied.To explore synaptic reorganization in the motor cortex after spinal cord injury,we established mouse models of T12 spinal cord hemi-section and then monitored the postsynaptic dendritic spines and presynaptic axonal boutons of pyramidal neurons in the hindlimb area of the motor cortex in vivo.Our results showed that spinal cord hemisection led to the remodeling of dendritic spines bilaterally in the motor cortex and the main remodeling regions changed over time.It made previously stable spines unstable and eliminated spines more unlikely to be re-emerged.There was a significant increase in new spines in the contralateral motor cortex.However,the low survival rate of the new spines demonstrated that new spines were still fragile.Observation of presynaptic axonal boutons found no significant change.These results suggest the existence of synapse remodeling in motor cortex after spinal cord hemi-section and that spinal cord hemi-section affected postsynaptic dendritic spines rather than presynaptic axonal boutons.This study was approved by the Ethics Committee of Chinese PLA General Hospital,China(approval No.201504168S)on April 16,2015.

Electro-optical dual modulation on resistive switching behavior in BaTiO3/BiFeO3/TiO2 heterojunction

The novel BaTiO3/BiFeO3/TiO2 multilayer heterojunction is prepared on a fluorine-doped tinoxide(FTO) substrate by the sol–gel method. The results indicate that the Pt/Ba TiO3/BiFeO3/TiO2/FTO heterojunction exhibits stable bipolar resistive switching characteristic, good retention performance, and reversal characteristic. Under different pulse voltages and light fields, four stable resistance states can also be realized. The analysis shows that the main conduction mechanism of the resistive switching characteristic of the heterojunction is space charge limited current(SCLC) effect. After the comprehensive analysis of the band diagram and the P–E ferroelectric property of the multilayer heterojunction, we can deduce that the SCLC is formed by the effect of the oxygen vacancy which is controlled by ferroelectric polarizationmodulated change of interfacial barrier. And the effective photo-generated carrier also plays a regulatory role in resistance state(RS), which is formed by the double ferroelectric layer Ba TiO3/BiFeO3 under different light fields. This research is of potential application values for developing the multi-state non-volatile resistance random access memory(RRAM) devices based on ferroelectric materials.

Cloning and characterization of Methoprene-tolerant(Met)and Kruppel homolog 1(Kr-h1)genes in the wheat blossom midge,Sitodiplosis mosellana

Juvenile hormone(JH),a growth regulator,inhibits ecdysteroid-induced meta-morphosis and controls insect development and diapause.Methoprene-tolerant(Met)and Krippel homolog I(Kr-h1)are two proteins involved in JH action.To gain some insight into their function in development of Sitodiplosis mosellana,an insect pest undergoing obligatory larval diapause at the mature 3rd instar stage,we cloned full-length complemen-tary DNAs of Met and Kr-h1 from this specics.SmMet encoded a putative protein,which contained three domains typical of the bHLH-PAS family and eight conserved amino acid residues important for JH binding.SmKr-h1 encoded a protein showing high sequence homology to its counterparts in other specics,and contained all eight highly conserved Zn-finger motifs for DNA-binding.Expression patterns of SmMet and SmKr hl were de-velopmentally regulated and JH III responsive as well.Their mRNA abundance increased as larvae entered carly 3rd instar,pre-diapause and maintenance stages,and peaked during post-diapause quiescence,a pattern correlated with JH titers in this species.Different from reduced expression of SmMer,SmKr-h1 mRNA increased at mid-to-late period of post-diapause development.Topical application of JH II on diapausing larvac also induced the two genes in a dose-dependent manner.Expression of SmuMer and SmKr-h1 clearly declined in the pre-pupal phase,and was significantly higher in female adults than male adults.These results suggest that JH-responsive SmMet and SmKr-h1 might play key roles in diapause induction and maintenance as well as in post-diapause quiescence and adult reproduction,whereas metamorphosis from larvae to pupac might be correlated with their reduced expression.

乙二胺四乙酸处理和水储存对不同树脂粘结剂与根管牙本质间粘结耐久性的影响(英文)

树脂粘结材料已广泛应用于临床,但其粘结耐久性仍不尽人意,导致牙本质粘结修复体远期存在继发龋、脱落率高等问题,成为目前亟需解决的关键问题。本文通过探讨不同树脂粘结剂(Supper Bond C&B、Panavia F和RelyX Unicem)与根管牙本质间粘结耐久性的差异,以及乙二胺四乙酸(EDTA)处理对不同树脂粘结剂粘结耐久性的影响,发现EDTA处理可以提高树脂粘结剂与根管牙本质间的粘结强度和粘结耐久性,从而可以提高修复体的远期粘结效果。另外,水储存可造成树脂粘结剂与根管牙本质间粘结强度下降。