Growth of carbon impurity density and adequate divertor wall temperature for fusion experimental reactors

Sudden increase of carbon impurity called carbon bloom has terminated the energy breakeven condition in the present large tokamak. In order to lengthen the burning plasma state in the next device, carbon bloom has to be well suppressed. The temporal evolution of carbon impurity density is analytically examined by using a simple one-point kinetic or zero-dimensional model including the effects of graphite erosions due to oxygen and ion, and gettering for oxygen due to boron or beryllium. The growth of carbon bloom due to radiation-enhanced sublimation is discussed based on the effective self-sputtering of carbon. Even when the self-sputtering yield is less than unity, carbon density is observed to continuously increase with the discharge time if the oxygen gettering action is not perfectly conducted. From the present analysis and data on the erosion of carbon materials, and the evaporation of gettering materials, it is suggested that the divertor wall temperature has to be kept less than approximately 900–1000°C to avoid the continuous growth of the carbon density.     

Value of repeat angiography in patients with spontaneous subcortical hemorrhage

BACKGROUND and PURPOSE: Neuroradiological investigations do not disclose a source of bleeding in some patients with spontaneous subcortical hemorrhage. These patients may harbor undetected vascular malformations and may be at risk of rebleeding in the future. We investigated patients with subcortical hemorrhage with use of repeat angiography and MRI to determine the incidence of occult vascular malformations and the risk of bleeding during follow-up. METHODS: We reviewed a consecutive series of 137 patients with subcortical hemorrhage during a 10-year period (June 1987 through June 1997). If the patient was <65 years old and the first angiogram and/or MRI did not show a source of bleeding, repeat angiography was recommended. All angiographic and MRI studies were reviewed. The relationship between the identified bleeding source and clinical variables such as patient age, sex, and history of hypertension and the size and location of the hematoma were examined. RESULTS: One hundred seven patients (78%) underwent angiography on admission, 10 (7%) had immediate surgery for hematoma without angiography, and 20 (15%) had neither angiography nor surgery. Overall, an etiology for the hemorrhage was found in 55 cases (40%). Vascular malformations were common in young patients without preexisting hypertension. A second angiogram was obtained in 22 patients, and 4 arteriovenous malformations were demonstrated. Rebleeding at the site of the initial hemorrhage was not observed after a mean follow-up of 68 months. CONCLUSIONS: Angiography performed acutely after hemorrhage may not demonstrate vascular malformations. Consideration should be given to repeat angiography in patients who do not have a specific cause for hemorrhage.     

The effects of word frequency for Japanese Kana and Kanji words in naming and lexical decision: Can the dual-route model save the lexical-selection account?

The effects of word frequency were examined for Japanese Kanji and Katakana words in 6 experiments. The sizes of frequency effects were comparable for Kanji and Katakana words in the standard lexical decision task. In the standard naming task, the frequency effect for Katakana words was significantly smaller than that for Kanji words. These results were consistent with the lexical-selection account of frequency effects offered by dual-route models. Contrary to this account, however, frequency effects were smaller for Katakana words than for Kanji words in go/no-go naming tasks, in which participants were asked to name a stimulus aloud only if it was a word. This Frequency?×?Script Type interaction was not the result of using a go/no-go task because the interaction disappeared in the go/no-go lexical decision task. These results pose a strong challenge for the lexical-selection account of frequency effects offered by dual-route models. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

1.50 /spl mu/m CW operation of GaInNAs/GaAs laser diodes grown by MOCVD

Room-temperature continuous-wave operation of a 1.5 /spl mu/m range GaInNAs laser grown by metal organic chemical vapour deposition is reported. The lasing wavelength of the GaInNAs/GaAs double quantum well laser was 1.50 /spl mu/m and the threshold current was 245 mA. The characteristic temperature between 10 and 50/spl deg/C was about 119 K under pulse operation.     

Index for predicting post-operative residual liver function by pre-operative dynamic liver SPET

To predict residual liver function before hepatic resection, we devised a predictive index by combining clearance values with functional liver volume measured by liver dynamic single photon emission tomography (SPET). Forty-seven patients with liver disease underwent liver dynamic SPET with 99Tcm-Sn colloid before hepatic resection. There were no operation-related deaths. Three patients died from hepatic failure more than 1 month following the operation. Their predictive indices were 0.24, 0.33 and 0.34. When the predictive index was above 0.35, no patient had symptoms of hepatic failure or died. Our data suggest that when the predictive index is above 0.35, there is a low probability of hepatic failure after hepatectomy.     

Silent myocardial ischemia in Kawasaki disease: evaluation of percutaneous transluminal coronary angioplasty by dobutamine stress testing

BACKGROUND: Myocardial ischemia and myocardial infarction are the most serious complications of coronary artery lesions in children with Kawasaki disease (KD). Therefore, early detection and treatment of myocardial ischemia in patients with KD is essential. We studied the effectiveness of percutaneous transluminal coronary angioplasty (PTCA) in patients with silent myocardial ischemia detected by dobutamine stress 99mTc myocardial scintigraphy (TMS), body surface mapping (BMS), and signal-averaged ECG late potentials (ELP). METHODS AND RESULTS: Eight of 76 asymptomatic patients with a coronary stenosis >25% and a positive dobutamine stress test were considered to have silent myocardial ischemia. All eight patients had >95% stenoses demonstrated by coronary angiography (CAG) just before PTCA. After PTCA, CAG showed that all of the coronary artery stenoses had been reduced to <50%. Additionally, intravascular ultrasonography (IVUS) performed in five patients before and after PTCA demonstrated adequate dilation of the coronary stenosis after PTCA. All eight patients underwent dobutamine stress TMS, BMS, and ELP 2 to 3 months after PTCA, which demonstrated no regions of myocardial ischemia. Approximately 6 months later, CAG was performed in all eight patients, and only one patient had developed restenosis. CONCLUSIONS: PTCA effectively dilates stenotic coronary arteries in children with KD. Moreover, dobutamine stress TMS, BMS, and ELP are useful for detecting silent myocardial ischemia and estimating the effectiveness of PTCA. Furthermore, IVUS is useful for evaluating the severity of coronary artery lesions before and after PTCA in patients with KD.     

The effects of word association and meaning frequency in a cross-modal lexical decision task: Is the priming due to "semantic" activation?

Two experiments examined the effects of priming by ambiguous, auditorily presented word primes. In related conditions, primes were followed by either associatively related or semantically related but associatively unrelated targets. When the targets were presented at prime offset (Exp 1), priming effects were observed only for associatively related targets, independent of meaning frequency (i.e., whether the target was related to the dominant or subordinate meaning of the ambiguous prime). When the targets were presented after a 700 msec delay (Exp 2), however, priming effects were observed only for targets related to the prime's dominant meaning, regardless of the nature of the prime-target relation. These results raise the strong possibility that previously reported differences in the nature of priming effects that had been ascribed to meaning frequency might actually be due to differences in associative strength. These results are discussed in terms of J. A. Fodor's (1983; 1990) "anti-semantic" modularity view. (PsycINFO Database Record (c) 2010 APA, all rights reserved)