We describe measurements of the decay of pure superfluid turbulence in superfluid 3He-B, in the low temperature regime where the normal fluid density is negligible. We follow the decay of the ...turbulence generated by a vibrating grid as detected by vibrating wire resonators. Despite the absence of any classical normal fluid dissipation processes, the decay is consistent with turbulence having the classical Kolmogorov energy spectrum and is remarkably similar to that measured in superfluid 4He at relatively high temperatures. Further, our results strongly suggest that the decay is governed by the superfluid circulation quantum rather than kinematic viscosity.
A new method was used for reconstituting active sodium deoxycholate solubilized Ca2+-ATPase of rabbit skeletal muscle sarcoplasmic reticulum. Removal of the detergent by dialysis at the pretransition ...temperature of the pure lipid (22 degrees C) favored the formation of sheet-like structures with a lipid and protein content close to that of the detergent-solubilized sample. Freeze-fracture electron micrographs revealed the Ca2+-ATPase to be organized in rows corresponding to the typical banded pattern seen in low-temperature freeze-fracture micrographs of pure lipid bilayers. Incubation of the sheetlike structures at a temperature (38 degrees C) above the pure lipid main phase transition (33.5 degrees C) caused closure of the sheets into vesicles displaying homogeneous intramembranous particle distributions, at least for membranes containing less than 150 lipids per Ca2+-ATPase. However, in membranes of higher lipid content, free lipid patches were seen both above and below the lipid phase transition. By use of high-sensitivity differential scanning calorimetry, three classes of excess heat capacity peaks were observed in the vesiculated samples. A broadened "free lipid" peak occurred for samples containing between 550 and 200 lipids per protein (Tm = 33.5 degrees C, as for the order-disorder transition in pure lipid vesicles). Between 200 and 150 lipids per Ca2+-ATPase, a broad shoulder became apparent in the range of 29-32 degrees C. Below 150 lipids per Ca2+-ATPase, a peak at 26-28 degrees C became increasingly prominent with lower lipid content. At a lipid to protein ratio of about 30, no peaks in heat capacity were observed. The temperature dependence of diphenylhexatriene fluorescence anisotropy revealed a similar pattern of membrane phase behavior, except that a phase transition was detected at 33.5 degrees C in all membranes studied. On the basis of these observations, we propose that the Ca2+-ATPase is surrounded by a "lipid annulus" of motionally inhibited lipid molecules that do not contribute to a calorimetrically detectable phase transition. Beyond the annulus, "secondary domains" of disrupted lipid packing account for the peak at 26-28 degrees C and the 29-32 degrees C shoulders. At high lipid to protein ratios, the secondary domains coexist with protein-free, lipid-bilayer patches, which account for the peak at 33.5 degrees C.
A new method was used for reconstituting active sodium deoxycholate solubilized Ca super(2+)-ATPase of rabbit skeletal muscle sarcoplasmic reticulum. Removal of the detergent by dialysis at the ...pretransition temperature of the pure lipid (22 degree C) favored the formation of sheet-like structures with a lipid and protein content close to that of the detergent-solubilized sample. Freeze-fracture electron micrographs revealed the Ca super(2+)-ATPase to be organized in rows corresponding to the typical banded pattern seen in low-temperature freeze-fracture micrographs of pure lipid bilayers. On the basis of the observations, the authors propose that the Ca super(2+)-ATPase is surrounded by a "lipid annulus" of motionally inhibited lipid molecules that do not contribute to a calorimetrically detectable phase transition. Beyond the annulus, "secondary domains" of disrupted lipid packing account for the peak at 26-28 degree C and the 29-32 degree C shoulders. At high lipid to protein ratios, the secondary domains coexist with protein-free, lipid-bilayer patches, which account for the peak at 33.5 degree C.
Investigation into the complex etiology of the postperfusion syndrome (PPS) has been limited by access to only retrospective human case studies, and performance of animal studies that examine ...biochemical predictors of injury rather than the PPS itself. To determine whether a reproducible canine model of the clinical syndrome was possible, seven dogs underwent cardiopulmonary bypass (CPB) with a bubble oxygenator for 0 (n = 1, sham), 2 (n = 1), 4 (n = 1), and 6 (n = 4) hours. Arterial oxygenation, chest radiographs, serum creatinine, and total leukocyte and platelet counts continued to change through the second postoperative day, illustrating the need for prolonged follow-up (48 hours) to accurately detect postperfusion organ dysfunction. The dogs that did not undergo CPB for 6 hours (n = 3) did not develop important pulmonary dysfunction postoperatively, but three of the four dogs undergoing 6 hours of CPB developed profound, persistent, arterial hypoxemia associated with radiographic, histologic, and hemodynamic evidence of severe PPS. Early evidence of renal dysfunction was also apparent within 84 hours of 6 hour CPB. It is concluded that the canine long duration (6 hour) CPB model, with prolonged (48 hour) postoperative monitoring, generates a reproducible, clinically relevant model of human PPS.
A Survey of Chinese Speech Recognition Fu, Stephen W K; Lee, C H; Clubb, Orville L
Communications of COLIPS,
06/1996, Letnik:
6, Številka:
1
Journal Article
This paper gives a comprehensive survey of the recognition techniques that have been applied to Chinese speech. Speech recognition systems for multi-syllable languages such as English have been ...successfully constructed in the last two decades. In recent years, Chinese speech recognition has become a fast developing area of research. This paper attempts to review & summarize techniques & results & highlight the following areas: the characteristics of spoken Chinese (especially Mandarin & Cantonese) that have significant bearing on the approaches taken for recognition; the speech recognition framework based on the bi-syllabic & tonal nature of Chinese spoken language; the recognition techniques based on bi-syllabic nature; the recognition of Chinese tones; & techniques based on language processing of words & sentence hypothesis. The results of various techniques are reported, compared, & commented on. 7 Tables, 2 Figures, 134 References. Adapted from the source document
The inhibition of cell cycle progression of a human pancreatic carcinoma line, MiaPaCa-2, by L-(alpha S, 5S)-alpha-amino-3-chloro-4,5-dihydro-5-isoxazoleacetic acid (Acividin), an antimetabolite and ...glutamine antagonist, was investigated by means of flow cytometry, cell cycle kinetics, and cell enumeration. Flow cytometric criteria for logarithmically growing MiaPaCa-2 cells were established. Logarithmically growing cells exposed to 50 microM Acivicin appeared to markedly reduce their rate of cell cycle progression after they passed a point in later G1 phase or in early S phase. MiaPaCa-2 cells grew in the presence of 50 microM Acivicin with a population-doubling time of approximately 74 hr compared to a 20-hr doubling time for controls. The inhibition of cell cycle progression was at least partially reversed by removal of the drug. Based on previous reports of the biochemical mechanisms of Acivicin actions, several additives to the tissue culture medium were tested for their ability to protect MiaPaCa-2 cells from inhibition of cell cycle progression. Those cultures which contained cytidine partially protected the cells from Acivicin. The mechanism of inhibited growth induced by exposure to Acivicin is likely a complex reaction to the inhibition of several enzyme systems.
China & Russia: The "Great Game" London, K. L.; Clubb, O. Edmund
The American Historical Review,
10/1973, Letnik:
78, Številka:
4
Book Review, Journal Article
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