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Background LAA occlusion has a similar stroke prevention efficacy compared to anticoagulation treatment for non-valvular atrial fibrillation. Objective The objective of this study was to assess the feasibility and safety of a modified Occlutech® left atrial appendage (LAA) closure device in a canine model. Methods The device was implanted in 10 dogs (33±1kg) using fluoroscopy and transesophageal echocardiography (TEE) guidance. The modified Occlutech® LAA occlusion device was compared with the current version, the Watchman device, and the Amplazter cardiac plug (ACP). LAA occlusion and anchoring to the LAA were evaluated. All dogs were assessed using angiography, TEE, and a gross anatomy examination. Results The 10 LAA occlusion devices were to be implanted into 10 dogs (5 modified Occlutech devices, 3 current version of Occlutech devices, 1 Watchman, and 1 ACP). LAA implantation was not performed in one dog due to transeptal puncture failure. The three current version of Occlutech devices were embolized immediately after implantation, so three modified devices of the same size were implanted securely without embolization. The mean implant size was 20.1±2.0mm. The devices chosen were a mean of 23.3±10.6% larger than the measured landing zone diameters. Post-implant angiography and TEE revealed well-positioned devices without pericardial effusion or impingement on surrounding structures. Conclusions The results of this acute animal study suggested that a modified Occlutech® LAA occlusion device was feasible and had greater anchoring performance in canines. Additional large clinical studies are needed to evaluate safety and efficacy.

Given the lack of promptness and inevitable use of additional contrast agents, the myocardial viability imaging procedures have not been used widely for determining the need to performing revascularization.This study is aimed to evaluate the feasibility of myocardial viability assessment, consecutively with diagnostic invasive coronary angiography (ICA) without use of additional contrast agent, using a novel hybrid system comprising ICA and multislice CT (MSCT).In all, 14 Yucatan miniature swine models (female; age, 3 months; weight, 28-30 kg) were subjected to ICA followed by balloon occlusion (90 minutes) and reperfusion of the left anterior descending coronary artery. Two weeks after induction of myocardial infarction, delayed hyperenhancement (DHE) images were obtained, using a novel combined machine comprising ICA and 320-channel MSCT scanner (Aquilion ONE, Toshiba), after 2, 5, 7, 10, 15, and 20 minutes after conventional ICA. The heart was sliced in 10-mm consecutive sections in the short-axis plane and was embedded in a solution of 1% triphenyltetrazolium chloride (TTC). Infarct size was determined as TTC-negative areas as a percentage of total left ventricular area. On MSCT images, infarct size per slice was calculated by dividing the DHE area by the total slice area (%) and compared with histochemical analyses.Serial MSCT scans revealed a peak CT attenuation of the infarct area (222.5 ± 36.5 Hounsfield units) with a maximum mean difference in CT attenuation between the infarct areas and normal myocardium of at 2 minutes after contrast injection (106.4; P for difference = 0.002). Furthermore, the percentage difference of infarct size by MSCT vs histopathologic specimen was significantly lower at 2 (8.5% ± 1.8%) and 5 minutes (9.5% ± 1.9%) than those after 7 minutes. Direct comparisons of slice-matched DHE area by MSCT demonstrated excellent correlation with TTC-derived infarct size (r = 0.952; P.001). Bland-Altman plots of the differences between DHE by MSCT and TTC-derived infarct measurements plotted against their means showed good agreement between the 2 methods.The feasibility of myocardial viability assessment by DHE using MSCT after conventional ICA was proven in experimental models, and the optimal viability images were obtained after 2 to 5 minutes after the final intracoronary injection of contrast agent for conventional ICA.

Castor beans (Ricinus communis) contain ricin, which is one of the most toxic substances of plant origin. Ricin toxicosis has been reported in different countries with usually ingestion of castor beans or plants in both animals and humans. However, ricin toxicosis by ingestion of some products containing castor oil cake has rarely been reported. This paper describes outbreaks of dog death by ricin toxicosis after accidental ingestion of the same soil conditioner. Fifteen dogs showed toxic symptoms such as severe vomiting, abdominal pain and hemorrhagic diarrhea, and then thirteen dogs died in a few days. The soil conditioner dogs ingested consisted of 10% castor oil cake containing ricin. On the basis of clinical signs, laboratory and pathologic findings, a diagnosis of ricin toxicosis was established in the present case. In comparison with previous cases by ingestion of castor beans, the dogs' morbidity was very high in the present case. The ingestion of castor oil cake may be more dangerous to life than the castor beans. It is because mortality by ingestion of castor beans depends on the degree of mastication of the beans, whereas ricin in oil cake is easily absorbed from the stomach and the intestines. As ricin is a heat-labile toxin, products containing ricin or oil cake should be properly treated with heat and have written caution sentences about toxicosis, and be kept out of reach of domestic animals and children.

We present an electrochemical impedance biosensor utilizing pyrolyzed carbon film as a working electrode material for aptamer-based thrombin detection. Batch-fabricated, smooth thin film carbon electrodes, which are fabricated by photolithography and photoresist thermal decomposition at high temperatures in inert ambient, are obtained for integrated electrochemical biosensors. To confirm the suitability of pyrolyzed carbon for use in an electrochemical biosensor, physical and electrical properties of carbon film pyrolyzed with a positive photoresist, AZ9260, were studied. Film thickness after pyrolysis was between 19% and 15% relative to the initial photoresist thickness and the cross-section was changed from rectangular to round shape due to the photoresist reflow characteristics. Resistivity of carbon thin film pyrolyzed at 1000 °C was 3 mΩ cm, which is comparable to that of highly boron-doped polysilicon. The pyrolysis temperature of 1000 °C was chosen in order to obtain carbon film with high conductivity for use as a working electrode. Thrombin aptamer was grafted onto the pyrolyzed carbon surface using carbodiimide-mediated chemistry, followed by Triton-X 100 and BSA treatment to reduce non-specific binding of thrombin. Electron-transfer resistance changes due to thrombin binding onto the carbon surface were measured using electrochemical impedance spectroscopy techniques. Thrombin concentrations between 0.5 nM and 500 nM were detected by electrochemical measurement. Pyrolyzed carbon can provide a new approach for miniaturization, integration, and low-cost fabrication in electrochemical biosensors.

The electric and the magnetic transport properties of the loop-type Al/Al 2 O 3 /Al single-electron tunneling device were studied. Even for the sample with charging energy about one order of magnitude greater than the Josephson coupling energy, the magnetoresistance showed h /2 e -oscillation at low bias voltage, attributed to the phase-coherent pair tunneling. The behavior of the magnetoresistance depends on the gate voltage, showing large and noiseless oscillations with the even number of excess charges but small and noisy oscillations with the odd number of excess charges in the metal islands.

The abundant supply of highly educated and motivated human resources, extremely favorable to the rapid growth of an export-led, labor-intensive manufacturing sector, has been the primary source of Korean economic development during the past quarter century. Now, the Korean economy is undergoing a tremendously rapid industrial structural change into an OECD-type of mature economy. This paper examines four sets of problems Korean labor will face in the transition period of the 1990s: changes in the age-sex-educational composition of the labor force; changes in the structure of labor demand, leading to possible skill mismatches; rising labor costs and reform in the remuneration system; moves toward participatory and democratic labor-management relations.