정재훈 교수

The priming of a docked synaptic vesicle determines the probability of its membrane (VM) fusing with the presynaptic membrane (PM) when a nerve impulse arrives. To gain insight into the nature of priming, we searched by electron tomography for structural relationships correlated with fusion probability at active zones of axon terminals at frog neuromuscular junctions. For terminals fixed at rest, the contact area between the VM of docked vesicles and PM varied >10-fold with a normal distribution

The effect of diamond like carbon (DLC) films, coated by a layer-by-layer technique using PECVD (plasma enhanced chemical vapor deposition) on the electron emission characteristics of molybdenum (Mo)-tip field emitter array (FEA) is examined. The turn-on voltage was lowered from 80 V for the Mo-tip to 65 V for the DLC-coated Mo-tip FEA while the maximum emission current was increased from 140 μA for the Mo-tip to 320 μA for the DLC-coated Mo-tip FEA composed of 900 emitters. For an anode current

Ipsilateral breast hypoplasia is a rare abnormality in Becker's nevus. The pathogenesis of the breast hypoplasia is not understood, but an increased level of androgenic receptor in the affected area may play a role. We report a case of Becker's nevus with ipsilateral breast hypoplasia. Spironolactone, an anti-androgenic agent, was tried for treatment of the hypoplasia, and, one month later, breast enlargement was seen in only the hypoplastic breast with Becker's nevus. This finding supports the

Long-term potentiation (LTP) is a cellular mechanism of learning and memory that results in a sustained increase in the probability of vesicular release of neurotransmitter. However, previous work in hippocampal area CA1 of the adult rat revealed that the total number of vesicles per synapse decreases following LTP, seemingly inconsistent with the elevated release probability. Here, electron-microscopic tomography (EMT) was used to assess whether changes in vesicle density or structure of vesicl

Specific cyclizations: The total synthesis of (−)-amphidinolide X was accomplished by employing a SmI2-mediated 5-exo cyclization of an aldehydo β-alkoxyvinyl sulfoxide and a ring-closing metathesis reaction (see scheme; Tol: tolyl).

2b Individual retrospective cohort study.

Stereoselective syntheses of 3-hydroxyoxanes were achieved via efficient chirality transfer in the SmI2-mediated cyclization reactions of aldehydo beta-alkoxyvinyl sulfoxides.

원격탐사 자료와 현장 자료를 이용한 산림 바이오매스 탄소량 추정은 전 세계적으로 각광을 받고 있으며, 국내의 경우 2010년 국립산림과학원에서 개발한 수종별 탄소배출계수를 통해 보다 정확한 탄소량 추정이 가능하게 되었다. 본 연구에서는 2006년부터 2009년까지 구축된 제5차 국가산림자원조사(National Forest Inventory, NFI) 자료를 기반으로 k-Nearest Neighbor(kNN) 알고리즘을 이용하여 충청북도 단양군의 지상부 바이오매스 탄소량을 추정하였다. 원격탐사 자료로는 계절 변화가 뚜렷한 한반도의 기후가 산림 지역의 분광 특성 및 이에 따른 탄소량 추정에 미치는 영향을 조사하기 위해 2004년부터 2005년까지 계절별로 취득된 Landsat TM 위성영상을 이용하였다. 분석결과 단양군 지역의 지상부 바이오매스 총 탄소량은 최대 3542768.49tonC에서 최소 3329037.51tonC 사이로 추정되었으나, 계절에 따른 특정 경향은 발견되지 않았다.

Active zone material is an organelle that is common to active zones along the presynaptic membrane of chemical synapses. Electron tomography on active zones at frog neuromuscular junctions has provided evidence that active zone material directs the docking of synaptic vesicles (SVs) on the presynaptic membrane at this synapse. Certain active zone material macromolecules connect to stereotypically arranged macromolecules in the membrane of undocked SVs, stably orienting a predetermined fusion dom

We have studied the enhancement of field-emission characteristics by hydrogen-free nitrogen-doped diamondlike carbon (DLC) coating on Mo-tip field emitter arrays by a layer-by-layer technique using plasma-enhanced chemical vapor deposition. The Spindt-type molybdenum tip is used as an emission source without a resistive layer on the silicon substrate. The maximum emission current for each pixel was increased from 160 to 1520 μA by a 20 nm N-doped DLC coating. Furthermore, the emission current fr

Synapses undergo transition from polyinnervation by multiple axons to single innervation a few weeks after birth. Synaptic activity of axons and interaxonal competition are thought to drive this developmental synapse elimination and tested as key parameters in quantitative models for further understanding. Recent studies of muscle synapses (endplates) show that there are also terminal Schwann cells (tSCs), glial cells associated with motor neurons and their functions, and vacant sites (or vacanc

Postsynaptic densities (PSDs) are large protein complexes associated with the postsynaptic membrane of excitatory synapses important for synaptic function including plasticity. Conventional electron microscopy (EM) typically depicts PSDs as compact disk-like structures of hundreds of nanometers in size. Biochemically isolated PSDs were also similar in dimension revealing a predominance of proteins with the ability to polymerize into an extensive scaffold; several EM studies noted their irregular

We have successfully developed the ultra‐high resolution 3,000ppi RGB direct patterning of OLED Micro‐display with high device performance. To fabricate this 3,000ppi RGB OLED Micro‐ display, FMM by UV Laser process was used and this FMM is manufactured by our unique Laser Patterning process. And red, green, and blue pixels were direct patterned by organic evaporation system with high precious alignment between Si substrate and FMM. To improve the device life time, very thin multi films of SiN/C

The emission stability of Mo-tip field emitter arrays (FEAs) has been improved. The effect of diamond-like carbon (DLC) films deposited using a layer-by-layer technique using plasma enhanced chemical vapor deposition on the electron emission characteristics of Mo-tip FEAs was examined. The turn-on voltage was lowered from 80 V for Mo-tip FEAs to 65 V for DLC-coated Mo-tip FEAs, and the maximum emission current increased from 140 μA for Mo-tip FEAs to 320 μA for DLC-coated Mo-tip FEAs composed of