<原著>肝右葉切除における短肝静脈, 右肝静脈処理のための前方アプローチ

A simple procedure of right hepatic lobectomy for bulky liver tumors is proposed. The procedure is named "Anterior approach", which is characterized by transection of hepatic parenchyma without mobilization and rotation of the right hepatic lobe. The transection directly reaches the ventral surface of the retrohepatic inferior vena cava first at the portion of caudate process. The hepatic parenchymal transection proceeds from ventral to dorsal and from caudal to cranial. Several dorsal short hepatic veins are severed on the ventral surface of the IVC and the right hepatic vein is finally severed from inside. This method enables the minimization of operative stress and is especially useful for cases with a huge tumor in the right hepatic lobe which invades the diaphragm or thoraco-abdominal wall.巨大肝腫瘍に対する合理的な肝右葉切除法としての前方アプローチを紹介する. 肝右葉切除の標準手技として, 右葉の授動と脱転がある. これは肝の右側から, 肝部下大静脈に注ぐ短肝静脈や右肝静脈の剥離と切離を行う方法であるが, 後区域や右葉全体を占める巨大肝腫瘍の場合には, それらの手技は困難なことが多く, また腫瘍の破裂をきたす恐れもあり危険を伴う. 前方アプローチは, 右葉の脱転を行わずに直接肝実質を切離して, 肝部下大静脈腹側面に到達し, 尾状葉突起から頭側に向かつて肝実質の離断を進める方法である. 肝部下大静脈腹側面に注ぐ短肝静脈を, 順次肝離断面側から剥離処理し, 最後に右肝静脈の離断も同様に行う. 横隔膜浸潤, 胸壁, 腹壁浸潤がある場合には, 肝切離が終了してから合併切除として最後に行う. また本法は, 脱転による残存肝の阻血, 門脈血液鬱滞を回避出来る利点があり, 肝ミトコンドリアの酸化還元状態を反映する動脈血中ケトン体比(AKBR)の術中低下も軽微であることが判明しており, 手術侵襲の点からみても有用である前方アプローチの良い適応は, 1)後区域, 又は右葉全体を占拠するような巨大肝腫瘍の場合, 2)腫蕩が右横隔膜, 胸壁, 腹壁に浸潤している場合, 3)右葉の腫瘍の下大静脈への浸潤が疑われ, 下大静脈合併切除の要否を判定する場合, 4)肝障害のために右葉切除を行うには機能的予備力の点で不安がある場合, などである

Quantitative potential measurements of nanoparticles with different surface charges in liquid by open-loop electric potential microscopy

Local potential distribution plays important roles in physical, chemical and biological processes at a solid/liquid interface. However, the measurement of a local potential distribution in liquid has been a long-standing challenge, which has hindered understanding of the mechanisms for the various interfacial phenomena. Recently, we have developed a method to overcome this problem [Kobayashi, Rev. Sci. Instrum. 81, 123705 (2010)], which is referred to as open-loop electric potential microscopy (OL-EPM). Here, we present its first application to quantitative measurements of local potential distribution in liquid. In OL-EPM, an ac bias voltage is applied between a tip and sample and the first and second harmonic cantilever oscillations induced by the electrostatic force are detected and used for the calculation of a potential value. In the equation for the potential calculation, here we introduce a correction factor to cancel out the error caused by the difference in the deflection sensitivity to the first and second harmonic electrostatic forces. With the improved method, we have performed potential measurements of two types of latex beads with different surface charges. The measured potential difference between the different types of latex beads approximately corresponds to their zeta potential difference, which demonstrates the quantitative capability of OL-EPM. © 2011 American Institute of Physics

Dual frequency open-loop electric potential microscopy for local potential measurements in electrolyte solution with high ionic strength

Recent development of open-loop electric potential microscopy (OL-EPM) has enabled to measure local potential distribution at a solid/liquid interface. However, the operating environment of OL-EPM has been limited to a weak electrolyte solution (<1 mM). This has significantly limited its application range in biology and chemistry. To overcome this limitation, we have developed dual frequency (DF) mode OL-EPM. In the method, an ac bias voltage consisting of two frequency components at f 1 and f 2 is applied between a tip and sample. The local potential is calculated from the amplitudes of the f 1 and f 1 - f 2 components of the electrostatic force. In contrast to the conventional single frequency (SF) mode OL-EPM, the detection of the 2f 1 component is not required in DF mode. Thus, the maximum bias modulation frequency in DF mode is twice as high as that in SF mode. The high bias modulation frequency used in DF mode prevents the generation of electrochemical reactions and redistribution of ions and water, which enables to operate OL-EPM even in a strong electrolyte solution. In this study, we have performed potential measurements of nanoparticles on a graphite surface in 1 and 10 mM NaCl solution. The results demonstrate that DF mode OL-EPM allows measurements of local potential distribution in 10 mM electrolyte solution. © 2012 American Institute of Physics

3次元原子間力顕微鏡による原子スケールでの局所水和構造状熊の解析方法の確立

金沢大学フロンティアサイエンス機構近年開発された3次元原子間力顕微鏡(3D-SFM)による原子スケールでの局所水和構造計測とそのメカニズムを明らかにするために、今年度は以下のことに取り組んだ。1)3D-SFM測定を行うために、本研究の観察対象であるフッ化カルシウム(CaF_2)(111)表面を原子スケールで長時間安定に観察できる溶液条件について検討した。超純水中ではCaF_2(111)表面の結晶モデルとよく一致した原子像が得られた。しかし、時間の経過とともに、CaF_2の溶解によって生じるカルシウムイオンと超純水中の水酸化物イオンが水酸化カルシウムとなって表面に大量に付着するために、3D-SFM測定を行うには難しい溶液条件ではないことが分かった。そこで、表面の溶解を抑えるために、過飽和溶液中で観察を行った。過飽和溶液中では、原子像を観察することはできた。しかし、溶液中の多量のカルシウムイオンやフッ素イオンが探針に吸着して、イメージング中にコントラストがたびたび急変するという現象が見られたことから、過飽和溶液も、3D-SFM測定に適した条件ではないということが分かった。次に、水酸化カルシウムの生成を抑えるために、過飽和溶液のpHを下げてイメージングを行った。その結果、溶解のない安定なテラスは見られたが、フッ化カルシウムが再結晶したものが付着したせいか、原子スケールではラフな表面であった。以上のことから、CaF_2(111)表面での3D-SFM測定に最適な溶液条件は非常なシビアなものであるという結論に至った。2)そこで、CaF_2の代わりに、炭酸カルシウム(CaCO_3)(101-4)表面の3D-SFM測定を行った。 CaCO_3(101-4)表面は、超純水中で1時間以上安定に原子像を取得することができることが分かった。そこで、この表面で3D-SFM測定を行った。その結果、第3水和層まで観察することに成功し、各水和層の水分子のサイトが理論結果とよく一致していることが分かった。これらの結果から、3D-SFMによる局所水和構造計測が非常に信頼性のある手法であることを実証した。研究課題/領域番号:23760028, 研究期間(年度):2011出典：研究課題「3次元原子間力顕微鏡による原子スケールでの局所水和構造状熊の解析方法の確立」課題番号23760028（KAKEN：科学研究費助成事業データベース（国立情報学研究所）） （https://kaken.nii.ac.jp/ja/grant/KAKENHI-PROJECT-23760028/）を加工して作

Atomic-scale processes at the fluorite-water interface visualized by frequency modulation atomic force microscopy

The crystal growth and dissolution processes of a fluorite (CaF 2) crystal have attracted much attention due to the importance in the industrial, environmental, and medical applications. While previous studies clarified nanoscale processes at the fluorite-water interface, atomic-scale origins of the processes have yet to be understood. In this study, we have investigated atomic-scale processes at the fluorite-water interface by frequency modulation atomic force microscopy (FM-AFM). We performed atomic-resolution imaging of a fluorite(111) surface in water (pH = 2 and 6.5), saturated solution (pH = 2 and 6), and supersaturated solution (pH = 6, σ = 10 and 100). Based on the results, we present three major findings. First, atomic-scale roughening of the crystal surface takes place at low pH due to the proton adsorption. Second, surface adsorbates with a subnanometer-scale height are formed on the crystal surface at high pH. They are most likely to be calcium hydroxo complexes physisorbed on the crystal surface. Finally, the formation of these complexes can be suppressed by increasing fluorite concentration owing to the increased proportion of Ca2+ and F- in the electric double layer. These findings mark an important step toward the full understanding of the physicochemical processes at the fluorite-water interface. © 2013 American Chemical Society

Nanoscale corrosion behavior of polycrystalline copper fine wires in dilute NaCl solution investigated by in-situ atomic force microscopy

In this study, nanoscale corrosion behavior of copper fine wires in dilute NaCl solution is studied by atomic force microscopy and electron backscatter diffraction. The dissolution rate of grains constituting the wires strongly depends on their crystallographic orientation. In pure water, the dissolution rate increases in the order of (111) < (001) < (110). Addition of Cl- dramatically increases the dissolution rate of the (111) surface to alter the order to (110) ≈ (001) ≈ (111) at 0.1 mM. These results show that the crystallographic orientation dependence is significantly changed by a slight increase of Cl- concentration in dilute solution. © 2016 Elsevier Ltd.Embargo Period 24 month

Visualizing Nanoscale Distribution of Corrosion Cells by Open-Loop Electric Potential Microscopy

Corrosion is a traditional problem but still one of the most serious problems in industry. To reduce the huge economic loss caused by corrosion, tremendous effort has been made to understand, predict and prevent it. Corrosion phenomena are generally explained by the formation of corrosion cells at a metal-electrolyte interface. However, experimental verification of their nanoscale distribution has been a major challenge owing to the lack of a method able to visualize the local potential distribution in an electrolytic solution. In this study, we have investigated the nanoscale corrosion behavior of Cu fine wires and a duplex stainless steel by in situ imaging of local corrosion cells by open-loop electric potential microscopy (OL-EPM). For both materials, potential images obtained by OL-EPM show nanoscale contrasts, where areas of higher and lower potential correspond to anodic areas (i.e., corrosion sites) and cathodic areas, respectively. This imaging capability allows us to investigate the real-time transition of local corrosion sites even when surface structures show little change. This is particularly useful for investigating reactions under surface oxide layers or highly corrosion-resistant materials as demonstrated here. The proposed technique should be applicable to the study of other redox reactions on a battery electrode or a catalytic material. The results presented here open up such future applications of OL-EPM in nanoscale electrochemistry. © 2016 American Chemical Society.Embargo Period 12 month