Design of a 300-kV gas environmental transmission electron microscope equipped with a cold field emission gun.

A new in situ environmental transmission electron microscope (ETEM) was developed based on a 300 kV TEM with a cold field emission gun (CFEG). Particular caution was taken in the ETEM design to assure uncompromised imaging and analytical performance of the TEM. Because of the improved pumping system between the gun and column, the vacuum of CFEG was largely improved and the probe current was sufficiently stabilized to operate without tip flashing for 2-3 h or longer. A high brightness of 2.5 × 10(9) A/cm(2) sr was measured at 300 kV, verifying the high quality of the CFEG electron beam. A specially designed gas injection-heating holder was used in the in situ TEM study at elevated temperatures with or without gas around the TEM specimen. Using this holder in a 10 Pa gas atmosphere and specimen temperatures up to 1000°C, high-resolution ETEM performance and analysis were achieved.

[Perioperative Management of a Patient with Severe Parkinson's Disease with Intravenous Levodopa Administration].

A 70-year-old man with severe Parkinson's disease was scheduled for thoracic aortic aneurysm resection and aortic valve replacement. We administered levodopa intravenously during the perioperative period to avoid the malignant syndrome which is reported to arise with abrupt cessation of anti-Parkinson's drugs. The dose of intravenous administration was tapered with the resumption of oral intake. No manifestation of malignant syndrome was observed. We measured blood concentrations of levodopa several times during the perioperative period. The concentration of levodopa during the surgery was relatively high; however no adverse events of overdose (e.g. dyskinesis) occurred. In the postoperative period, administration of levodopa was changed to the oral route and serum levels of levodopa showed a notable decrease, the cause of which may be poor absorption through the digestive system during the perioperative period. Therefore, in the peri- and post-operative periods, it is necessary to take great care when reducing the infusion dose.

[Case of papillary fibroelastoma which caused cardiopulmonary arrest leading to emergent extirpation surgery].

A 73-year-old woman with cardiac tumor arising from aortic valve was scheduled for extirpation surgery. She has a symptom of chest discomfort during her walk. Contrasted CT scan around the aortic valve demonstrated a 1 cm-size tumor close to the left coronary inlet. Coronary blood flow was preserved. On the day of admission she became unconscious during preoperative interview with the surgeon. Cardiopulmonary resuscitation was immediately initiated and she regained her consciousness. Emergency operation was scheduled and started about two hours after the event of syncope. Cardiac tumor attached to the left cusp of the aortic valve was found and later identified as papillary fibroelastoma by pathological diagnosis. She was discharged on the 13th day from admission without neurological deficit. Occlusion of the left coronary artery inlet was strongly suspected from preoperative event of her syncope. Cardiac tumor around aortic value may cause significant derangement of circulation, and we should closely monitor the patient's status and prompt operation was indicated especially when tumor is impeding coronary artery inlet.

Development of a technique for in situ high temperature TEM observation of catalysts in a highly moisturized air atmosphere.

To clarify the influence of moisture on the structural changes of heated nano materials, in situ high temperature transmission electron microscopy (TEM) has been carried out using a conventional analytical TEM combined with a gas injection-specimen heating holder. Air with high moisture content, above 94% relative humidity (RH), from a humidifier was directly injected onto the heated platinum catalyst dispersed on carbon black (Pt/CB), and the morphological changes of the specimens were observed at high magnification dynamically. The result of the experiment was compared with a result obtained from an experiment using air with a low moisture content, 34% RH. Active movement of the Pt particles, leading agglomeration and grain growth, occurred prior to degradation of the CB support at high moisture content. In contrast, the degradation of the CB support leading agglomeration and grain growth of the Pt particles occurred before the displacement of the Pt particles on the CB supports in a low humidity environment.

Development of a high temperature-atmospheric pressure environmental cell for high-resolution TEM.

An environmental cell for high-temperature, high-resolution transmission electron microscopy of nanomaterials in near atmospheric pressures is developed. The developed environmental cell is a side-entry type with built-in specimen-heating element and micropressure gauge. The relationship between the cell condition and the quality of the transmission electron microscopic (TEM) image and the diffraction pattern was examined experimentally and theoretically. By using the cell consisting of two electron-transparent silicon nitride thin films as the window material, the gas pressure inside the environmental cell is continuously controlled from 10(-5) Pa to the atmospheric pressure in a high-vacuum TEM specimen chamber. TEM image resolutions of 0.23 and 0.31 nm were obtained using 15-nm-thick silicon nitride film windows with the pressure inside the cell being around 5 × 10(-5) and 1 × 10(4) Pa, respectively.

Development of an analytical environmental TEM system and its application.

Many automotive materials, such as catalysts and fuel cell materials, undergo significant changes in structure or properties when subjected to temperature change or the addition of a gas. For this reason, in the development of these materials, it is important to study the behavior of the material under controlled temperatures and gaseous atmospheres. Recently, a new environmental transmission electron microscope (TEM) has been developed for observation with a high resolution at high temperatures and under gaseous atmospheres, thus making it possible to analyze reaction processes in details. Also, the new TEM provides a high degree of reproducibility of observation conditions, thus making it possible to compare and validate observation of various specimens under a given set of conditions. Furthermore, easiness of gas condition and temperature control can provide a powerful tool for the studying of the mechanism of material change, such as oxidation and reduction reactions.

Anesthetic management for severe aortic regurgitation in an infant repaired by Ross procedure.

We report the anesthetic management of a 7-month-old male infant with severe aortic regurgitation (AR) scheduled for the Ross procedure. To the best of our knowledge, this is the first report from the viewpoint of anesthetic management for the Ross procedure performed in an infant. He had been suffering from severe AR that occurred suddenly when he was 5 months old. The cause of the AR was considered to be spontaneous rupture of a fenestrated aortic valve, owing to congenital tissue defect in part of the aortic valvular leaflet. The Ross procedure was scheduled to be performed under general anesthesia using deep hypothermic cardiopulmonary bypass (CPB). Continuous infusion of nitroglycerin was started during CPB and continued after CPB to dilate the newly implanted coronary arteries for the prevention of myocardial ischemia and to decrease afterload and pulmonary vascular resistance. Weaning from CPB was performed without difficulty, but after the prolonged CPB he had a bleeding tendency that needed transfusion and a hemostatic drug. Monitoring with transesophageal echocardiography was very useful for evaluating myocardial ischemia, and for assessing the procedure and the completion of surgical repair. His postoperative course was uneventful and he was discharged on the 25th postoperative day.

Development of a gas injection/specimen heating holder for use with transmission electron microscope.

A new gas injection/specimen heating holder is developed for the purpose of in situ observation of gas reaction of materials at high temperatures in a transmission electron microscope at near-atomic resolution. A fine tungsten wire is employed as a heating element of the holder and a battery is used as the power source. Gas was injected onto specimens in the form of particles lying on the heating element via a nozzle. The maximum pressure near specimens was middle of 10(-2) Pa, while the pressure in the electron-gun chamber was kept to 2 x 10(-4) Pa. This gas injection/specimen heating holder was applied to observe solid-gas reactions. The reactions observed include oxidation of pure In into In2O3, reduction of SiO2 into Si and re-oxidation of Si into SiO2.