発作後subtraction SPECTを用いた脳卒中後てんかんにおける遷延性過灌流の可視化

京都大学新制・論文博士博士(医学)乙第13397号論医博第2221号新制||医||1051(附属図書館)(主査)教授 伊佐 正, 教授 中本 裕士, 教授 渡邉 大学位規則第4条第2項該当Doctor of Medical ScienceKyoto UniversityDFA

Real-time atomic-resolution imaging of crystal growth process in water by phase modulation atomic force microscopy at one frame per second

Recent advancement in dynamic-mode atomic force microscopy (AFM) has enabled its operation in liquid with atomic-scale resolution. However, its imaging speed has often been too slow to visualize atomic-scale dynamic processes. Here, we propose a method for making a significant improvement in the operation speed of dynamic-mode AFM. In this method, we use a wideband and low-latency phase detector with an improved algorithm for the signal complexification. We demonstrate atomic-scale imaging of a calcite crystal growth process in water at one frame per second. The significant improvement in the imaging speed should enable various studies on unexplored atomic-scale interfacial processes. © 2013 AIP Publishing LLC

Ion-specific nanoscale compaction of cysteine-modified poly(acrylic acid) brushes revealed by 3D scanning force microscopy with frequency modulation detection

Stimuli-responsive polyelectrolyte brushes adapt their physico-chemical properties according to pH and ion concentrations of the solution in contact. We synthesized a poly(acrylic acid) bearing cysteine residues at side chains and a lipid head group at the terminal, and incorporated them into a phospholipid monolayer deposited on a hydrophobic silane monolayer. The ion-specific, nanoscale response of polyelectrolyte brushes was detected by using three-dimensional scanning force microscopy (3D-SFM) combined with frequency modulation detection. The obtained topographic and mechanical landscapes indicated that the brushes were uniformly stretched, undergoing a gradual transition from the brush to the bulk electrolyte in the absence of divalent cations. When 1 mM calcium ions were added, the brushes were uniformly compacted, exhibiting a sharper brush-to-bulk transition. Remarkably, the addition of 1 mM cadmium ions made the brush surface significantly rough and the mechanical landscape highly heterogeneous. Currently, cadmium-specific nanoscale compaction of the brushes is attributed to the coordination of thiol and carboxyl side chains with cadmium ions, as suggested for naturally occurring, heavy metal binding proteins

Improvements in fundamental performance of liquid-environment atomic force microscopy with true atomic resolution

Recently, there have been significant advancements in liquid-environment atomic force microscopy (AFM) with true atomic resolution. The technical advancements are followed by a rapid expansion of its application area. Examples include subnanometer-scale imaging of biological systems and three-dimensional measurements of water distributions (i.e., hydration structures) and fluctuating surface structures. However, to continue this progress, we should improve the fundamental performance of liquid-environment dynamic-mode AFM. The present AFM technique does not allow real-time imaging of atomic-scale dynamic phenomena at a solid-liquid interface. This has hindered atomic-level understanding of crystal growth and dissolution, catalytic reactions and metal corrosion processes. Improvement in force sensitivity is required not only for such a high-speed imaging but also for various surface property measurements using a high-resolution AFM technique. In this review, we summarize recent works on the improvements in the force sensitivity and operation speed of atomic-resolution dynamic-mode AFM for liquid-environment applications. © 2015 The Japan Society of Applied Physics.Embargo Period 12 month

Separate-type scanner and wideband high-voltage amplifier for atomic-resolution and high-speed atomic force microscopy

We have developed a liquid-environment atomic force microscope with a wideband and low-noise scanning system for atomic-scale imaging of dynamic processes at solid/liquid interfaces. The developed scanning system consists of a separate-type scanner and a wideband high-voltage amplifier (HVA). By separating an XY-sample scanner from a Z-tip scanner, we have enabled to use a relatively large sample without compromising the high resonance frequency. We compared various cantilever- and sample-holding mechanisms by experiments and finite element analyses for optimizing the balance between the usability and frequency response characteristics. We specifically designed the HVA to drive the developed scanners, which enabled to achieve the positioning accuracy of 5.7 and 0.53 pm in the XY and Z axes, respectively. Such an excellent noise performance allowed us to perform atomic-resolution imaging of mica and calcite in liquid. Furthermore, we demonstrate in situ and atomic-resolution imaging of the calcite crystal growth process in water. © 2013 AIP Publishing LLC