Influence of the Catalyst Layer Structure Formed by Inkjet Coating Printer on PEFC Performance.

In this study, we investigated the influence of the Catalyst-Layer (CL) structure on Polymer Electrolyte Fuel Cell (PEFC) performance using an inkjet coating printer, and we especially focused on the CL thickness and the electrode area. In order to evaluate the influence of CL thickness, we prepared four Membrane Electrode Assemblies (MEAs), which have one, four, five and six CLs, respectively, and evaluated it by an overpotential analysis. As a result, the overpotentials of an activation and a diffusion increased with the increase of thickness of CL. From Energy Dispersive X-ray spectroscopy (EDX) analysis, because platinum twines most ionomers and precipitates, the CL separates into a layer of platinum with a big grain aggregate ionomer and the mixing layer of platinum and ionomer during the catalyst ink drying process. Consequently, the activation overpotential increased because the three-phase interface was not able to be formed sufficiently. The gas diffusivity of the multilayer catalyst electrode was worse than that of a single layer MEA. The influence of the electrode area was examined by two MEAs with 1 and 9 cm2 of electrode area. As a result, the diffusion overpotential of 9 cm2 MEA was worse than 1 cm2 MEA. The generated condensate was multiplied and moved to the downstream side, and thereafter it caused the flooding/plugging phenomena.

Endovascular Treatment of Left Subclavian Artery Pseudoaneurysm after Clavicle Fracture in an Elderly Adult with a 40-Year History of Behçet's Disease.

Behçet's disease (BD) is a rare chronic systemic vasculitis of unknown etiology that presents in young adults. We report a very rare case of a left subclavian artery pseudoaneurysm identified after a left clavicle fracture in a 70-year-old man with a 40-year history of intestinal BD. The patient received fixation by banding to treat a fracture after falling from a bed about 5 months previously, and he was referred to our hospital due to the finding of a left subclavian pulsatile mass. As enhanced computed tomography showed a left subclavian artery pseudoaneurysm, it was repaired using an endovascular stent graft.

Influence of ethanol-induced pulmonary embolism on hemodynamics in pigs.

AIMS AND OBJECTIVES: Ethanol is widely used for the embolization treatment of vascular malformations, but it can also cause serious complications such us pulmonary hypertension, cardiopulmonary collapse and death. The complications are considered secondary to pulmonary vasospasm and ethanol-induced sludge embolism, etc., We studied the hemodynamic effects of intravenous absolute ethanol injection and ethanol sludge injection in pigs. MATERIALS AND METHODS: A total of 5 pigs underwent intravenous injection of ex vivo generated ethanol-induced sludge in which residual ethanol was removed (Group S) and 4 pigs underwent intravenous injection of absolute ethanol (Group E). Hemodynamic parameters related to the pulmonary and systemic circulation were compared between the groups. RESULTS: Transient pulmonary hypertension was observed in both groups and the hemodynamic changes were similar in both groups. CONCLUSIONS: Sludge can induce transient pulmonary hypertension or cardiopulmonary collapse, without ethanol and may be the mechanism by which ethanol induces its adverse hemodynamic effects.

Balloon-assisted coil embolization of the celiac trunk before endovascular aortic repair of thoracoabdominal aortic aneurysm.

PURPOSE: Celiac trunk coil embolization before thoracic endovascular aneurysm repair (TEVAR) of a thoracoabdominal aortic aneurysm involving the celiac trunk can prevent type II endoleaks. One disadvantage of conventional coil embolization is the risk of coil displacement. We performed coil embolization under balloon occlusion of the celiac trunk to address this issue. MATERIALS AND METHODS: Between December 2008 and January 2011, 5 patients (3 men and 2 women, mean age 76 years) were included in this study. For all patients, after confirming the collateral blood flow from the superior mesenteric artery via the pancreaticoduodenal arcades by using the balloon occlusion test, celiac trunk coil embolization proceeded under balloon occlusion of the proximal part of the celiac trunk. RESULTS: Balloon-assisted coil embolization of the celiac trunk was completed for all patients without any complications. All coils were deployed as planned in the short segment of the celiac trunk without displacement. Coil migration, ischemic complications, and endoleaks via the celiac trunk did not arise in any of the patients over a follow-up period of 77-637 (mean 258) days. CONCLUSIONS: Balloon-assisted coil embolization of the celiac trunk before TEVAR could be a feasible treatment option for suitable patients.

Development of a new hanging-type esophageal stent for preventing migration: a preliminary study in an animal model of esophagotracheal fistula.

PURPOSE: Covered, self-expandable metallic stents (SEMS) have been enthusiastically adopted for the treatment of esophagotracheal fistula, but problems with stent migration have yet to be resolved. To overcome this problem, we have developed a new hanging-type esophageal stent designed to prevent migration, and we conducted an animal study to assess the efficacy of our method. METHODS: A total of six female pigs were used in this study. The main characteristic of our stent was the presence of a string tied to the proximal edge of the stent for fixation under the skin of the neck. The first experiment was performed to confirm technical feasibility in three pigs with esophagotracheal fistula. The second experiment was performed to evaluate stent migration and esophagotracheal fistula in three pigs. RESULTS: Creation of the esophagotracheal fistula and stent placement were technically successful in all pigs. In the first experiment, esophagotracheal fistula was sealed by stent placement. In the second experiment, no stent migration was seen 11 or 12 days after stent placement. Gross findings showed no fistulas on the esophageal or tracheal wall. CONCLUSIONS: Our new hanging-type esophageal stent seems to offer a feasible method for preventing stent migration.

Transfemoral approach using a 3.5-French catheter system for use in transcatheter arterial chemoembolization in patients with hepatocellular carcinoma: technical assessment.

BACKGROUND/AIMS: To evaluate the technical feasibility of the transfemoral approach using a 3.5-Fr catheter system for transcatheter arterial chemoembolization (TACE) in patients with hepatocellular carcinoma (HCC). METHODOLOGY: This study included 81 patients with unresectable HCC who underwent transfemoral TACE using a 3.5-Fr catheter system without a sheath between August 2008 and June 2010. A 2.0-Fr microcatheter was used within a 3.5-Fr catheter in all cases. After completion of TACE, manual compression was applied to the puncture site for 5min, and patients were kept supine for 1h. The success rate and periprocedural complications of TACE were evaluated. RESULTS: Transfemoral TACE with a 3.5-Fr catheter system was carried out in 103 transfemoral TACE sessions. TACE was performed for 103 subsegmental arteries, 19 segmental arteries, 13 lobar arteries, 8 right inferior phrenic arteries, 1 left inferior phrenic artery, and 1 inferior pancreatico-duodenal artery. Image quality in all hepatic angiograms using 3.5-Fr catheters was satisfactory. Technical success was achieved in 97 (94%) out of 103 procedures. In only 1 patient, it took 10min to achieve hemostasis. There were no periprocedural complications. CONCLUSIONS: Transfemoral TACE using a 3.5-Fr catheter system is technically feasible and enables early ambulation safely in patients with HCC.

Development of a re-positionable aortic stent-valve: a preliminary study in swine.

BACKGROUND: Placement of aortic stent-valves in the proper position is difficult due to the high velocity and oscillation of blood flow and anatomical characteristics. To address this problem, a re-positionable stent-valve was designed and examined in a preliminary animal experiment. METHODS: Protocols for this animal study were approved by the institutional Animal Care and Use Committee. An umbrella-shaped polyurethane valve was attached at the tip of newly devised re-positionable metallic stent. The prosthesis (re-positionable stent-valve) was implanted in 5 female pigs via the right carotid artery using a 10-F introducer (Group A). As a control, the stent-without-valve was implanted in 4 female pigs (Group B). Efficacy of the valve was assessed by aortography and aortic pressure measurement. Animals were sacrificed 1 hour after stent-valve implantation for macroscopic examination. RESULTS: The stent-valve was successfully implanted in all pigs. In Group A, aortography showed good function of the polyurethane valve. No significant change in diastolic pressure was noted during valve testing. In Group B, aortography and aortic pressure measurement showed massive aortic regurgitation following dysfunction of the native aortic leaflets. Post-mortem examination showed small amounts of thrombus inside the polyurethane umbrella in Group A. CONCLUSION: Placement of the re-positionable stent-valve seems feasible and effective. However, the problem of thrombus formation inside the umbrella valve should be solved in future studies.

Heat distribution in the spinal canal during radiofrequency ablation for vertebral lesions: study in swine.

PURPOSE: To prospectively evaluate the safety of radiofrequency (RF) ablation for vertebral lesions by monitoring the temperature in swine vertebral models with and without a cortical bone defect. MATERIALS AND METHODS: The institutional animal care and use committee approved the animal studies. In vivo and ex vivo studies were performed. In the in vivo study, 20 lumbar vertebrae from six swine were locally heated by using 1- or 2-cm active-tip internally cooled electrodes. In the ex vivo study, 12 fresh pig cadaver lumbar vertebrae were extracted from four swine, and spinal tumor models with or without cortical bone defect were created by stuffing a cavity with muscle tissue and locally heated by using a 1-cm active-tip internally cooled electrode. The temperature was monitored in the spinal canal and around the vertebral body during ablation. Mann-Whitney U test was used to indicate a significant difference between groups by using 1- and 2-cm active tip in the in vivo study and between groups with and without cortical defect in the ex vivo study. RESULTS: In the in vivo study in which 1- and 2-cm active-tip needles were used, the temperature in the spinal canal rose to 38.2 degrees C +/- 2.7 (standard deviation) and 45.5 degrees C +/- 6.2, respectively. The latter was significantly higher than the former (P < .001). In the ex vivo study in which tumor models with or without a cortical bone defect were used, the temperature in the spinal canal rose to 48.4 degrees C +/- 6.2 and 31.3 degrees C +/- 3.4, respectively. The former was significantly higher than the latter (P < .001). CONCLUSION: For in vivo cases with a 2-cm active tip and ex vivo cases with a vertebral posterior bone defect, the temperature rose to over 45 degrees C, potentially injuring the spinal cord and peripheral nerves.

CT-guided transthoracic needle biopsy using a puncture site-down positioning technique.

OBJECTIVE: We have developed a new CT-guided technique using puncture site-down positioning during the biopsy. The goal of our study was to determine the efficacy and safety of this technique for biopsy of lung lesions compared with the standard technique. MATERIALS AND METHODS: Medical records of 236 patients who underwent CT-guided transthoracic needle biopsy were retrospectively evaluated. This study included 89 cases that were biopsied using the standard technique (group A) and 147 cases that were biopsied using the puncture site-down positioning technique (group B). A 20-gauge automated cutting needle without coaxial technique was used in all patients. Medical records were reviewed for lesion size and location, biopsy results, and complications. RESULTS: When using the standard technique, the sensitivity for malignant lesions was 96.1%; the sensitivity for benign lesions, 92.1%; and diagnostic accuracy, 94.4%. Thirty-seven patients (41.6%) had pneumothorax, with 16 (18.0%) requiring chest tube placement. When using the puncture site-down positioning technique, the sensitivity for malignant lesions was 95.4%; the sensitivity for benign lesions, 93.3%; and diagnostic accuracy, 94.6%. Nineteen patients (12.9%) had pneumothorax, with four (2.7%) requiring chest tube placement. Other complications were minimal. CONCLUSION: CT-guided transthoracic needle biopsy using the puncture site-down positioning technique is an effective and safe procedure with a high diagnostic accuracy and low complication rate. This new technique is especially useful in reducing the rate of pneumothorax.

Localization of chyle leakage site in postoperative chylothorax by oral administration of I-123 BMIPP.

The authors present a 71-year-old woman who had a right chylothorax after right upper lobectomy for lung cancer. As the chylothorax was considered to be due to thoracic duct injury at the time of operation, lymphoscintigraphy was performed by oral administration of I-123 beta-methyl-iodophenyl pentadecanoic acid (BMIPP). After visualization of the stomach and intestine, abnormal accumulation of the radiotracer was found initially around the right pulmonary hilum and then spread laterally in the upper pleural cavity, indicating chyle leakage in the region of the right pulmonary hilum. Scintigraphic finding was well correlated with the subsequent thoracoscopic observation, showing chyle leakage from a lymphatic tributary near its confluence to the thoracic duct at the level of the azygos continuation. The disruption site was ligated by video-assisted-thoracoscopic-surgery procedure with successful termination of the chyle leakage. Lymphoscintigraphy by oral administration of I-123 BMIPP is thought to be a useful method for localization of chyle leakage in patients with chylothorax induced by thoracic surgery.