We report an instability of 4He crystal surface during a large modification of its shape observed by schlieren photography. 4He crystal was nucleated on an ultrasound transducer which was placed in the upper part of the sample cell facing the bottom.
The crystal was grown on the transducer and the lowest part of it eventually touched the bottom of the cell. Almost immediately,
the crystal started to change shape very quickly to adjust itself to the new boundary condition. During this large deformation,
the hexagonal shape of the crystal surrounded by facets became unstable and the surface became corrugated. The corrugation
pattern during the deformation was observed by a high-speed camera. The results were compared with Kelvin-Helmholtz type instability
which Uwaha and Nozières predicted.
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We studied in vitro spontaneous and ultraviolet light (UV)-induced lymphocyte apoptosis in patients with systemic lupus erythematosus (SLE, n = 11), cutaneous lupus erythematosus (CLE, n = 8), and other collagen diseases (n = 6), as well as normal individuals (n = 6). Apoptosis was confirmed by the presence of a 180 bp DNA ladder on gel electrophoresis. UVB-induced apoptosis was observed in 4 of 11 patients with SLE (36.3%), 3 of 8 patients with CLE (37.5%) and 2 of 6 patients (33.3%) with other collagen diseases. There was no clinical correlation between clinical photosensitivity and UV-induced apoptosis. Similarly, spontaneous apoptosis was also found in lymphocytes from patients with diseases other than SLE. No apoptosis was found in normal subjects with or without UVB irradiation (25 mJ/cm2). These data suggest that UV-induced lymphocyte apoptosis may not be specific to SLE but may be common in collagen diseases. 相似文献
The environmental stress cracking (ESC) of acrylonitrile-butadiene-styrene (ABS) copolymer caused by a non-ionic surfactant (poly-oxyethylene alkylether) was studied by constant-load tensile creep tests and edge crack tension (ECT) tests. The fracture surfaces were investigated by a scanning electron microscope (SEM) and the morphology of the crack tip was investigated by a transmission electron microscope (TEM). It was found that the results of the creep tests performed in the non-ionic surfactant were very different from those performed in air. SEM images of the fracture surfaces showed that there were three different mechanisms of fracture and that specimens had a tendency to rupture by ESC when the stress was small. The results of the ECT tests and the TEM images showed that the change in the mechanism of the fracture was attributable to the change of morphology at the crack tip. 相似文献
Creating back-of-the-book indexes is a difficult task involving intelligent and clerical processes. Programs have generally not achieved the level of intelligence required to perform the intelligent process of selecting terms for the index. Semi-automatic indexing programs perform the clerical process of preparing entries once the terms have been selected. The programs do not provide assistance in term determination and most require flooding the text with indexing commands. indx differs from other semi-automatic indexing programs mainly because it does not require the insertion of indexing commands into the text to be indexed. The method by which indx assists in the creation of an index is introduced and compared with the characteristics of the other programs. This method includes the use of a program that aids the term determination process. The design, implementation, and application of indx are presented. Areas in which indx may be improved or enhanced are identified. An index of this paper created with indx is included as an example. 相似文献
Transmission electron microscopy has been widely used to investigate the radiation-damage microstructures, but has limitations when observing point defects due to its resolution limit. In the present study, a dilute Cu-Co alloy, which is a typical precipitation-hardened alloy, has been selected to investigate the formation and the mobility of point defects upon ion irradiation, during which the coherent precipitates lose their coherency and exhibit incoherent strain contrast, and the coherency loss can be used to detect the point defects. 相似文献
A three‐component reaction of 3‐(tri‐n‐butylstannyl)allyl acetates, aldehydes, and triorganoboranes in the presence of a palladium‐Xantphos catalyst system predominately gave (E)‐anti‐homoallylic alcohols with high diastereoselectivity and good to high levels of alkene stereocontrol. An efficient chirality transfer was observed when an enantioenriched substrate was employed. The reaction was initiated by the formation of an allylic gem‐palladium/stannyl intermediate, which subsequently underwent allylation of the aldehyde by an allyltributyltin followed by a coupling reaction of the in‐situ‐generated (E)‐vinylpalladium acetate with the triorganoborane.
Inefficient removal of estrone (E1) in wastewater treatment plants (WWTPs) causes feminizing effects in male aquatic creatures. As E1 is mainly removed by biodegradation, investigation of E1 degradation is important to determine better removal strategies. Using microautoradiography-fluorescence in situ hybridization (MAR-FISH), we demonstrated that the structures of [3H]E1-incorporating bacterial communities were different at different E1 concentrations applied to activated sludge. At 200 μg/L E1, almost all [3H]E1-incorporating cells were associated with either Betaproteobacteria or Gammaproteobacteria (60% and 40% of MAR (+) cells, respectively). The proportion of Betaproteobacteria and Gammaproteobacteria in the total number of [3H]E1-incorporating cells decreased as the concentration of E1 decreased. In contrast, the proportion of Alphaproteobacteria in the total number of [3H]E1-incorporating cells increased as the concentrations of E1 decreased. At the lowest applied concentration (540 ng/L), almost all the [3H]E1-incorporating cells were Alphaproteobacteria (96%). The results of MAR-FISH applied to sludge samples collected from various plant locations and activated sludge processes, and during different seasons also demonstrated the high contribution of Alphaproteobacteria to the entire E1-degrading bacterial community (50.4 ± 11% of the total number of [3H]E1-incorporating cells) at 1 μg/L E1. Since the E1 concentration in domestic wastewater is at sub-μg/L levels, the key E1 degraders in activated sludge of domestic WWTPs are probably be Alphaproteobacteria. All [3H]E1-incorporating Alphaproteobacteria were hybridized with probe ALF968. Few MAR (+) cells were Sphingomonadales. An E1-degrading bacterial community at low E1 concentration appeared to consist of diverse bacterial groups of Alphaproteobacteria. This study suggested that substrate concentration is an essential factor for revealing E1-degrading bacteria in complex communities. 相似文献
The mean concentrations and daily intake of four antifungal agents were estimated based on the results of an analysis of 7,005 samples of food obtained in official inspections by Japanese local governments in fiscal year 1998. The mean concentration of diphenyl was 0.0004% of the allowable limit, and those of imazalil, o-phenylphenol, and thiabendazole were 14.0%, 3.5%, and 5.7%, respectively. The daily intakes of these antifungal agents per person, estimated from their concentrations and the daily consumption of the foods, were 0.000326, 1.89, 11.5, and 23.3 micrograms, respectively, and assuming a body weight of 50 kg, the amounts of these antifungal agents consumed were 0.000013%, 0.15%, 0.12%, and 0.47% of the acceptable daily intake, respectively. These values are similar to the values obtained on the basis of the results of the official inspection in fiscal years 1994 and 1996, except that the amount of diphenyl is much lower (1/100). 相似文献
Breadmaking properties, such as bread height and specific volume, were improved in bread, made with wheat flour blended with Welsh onion (Allium fistulosum L.) powder, which is high in di‐n‐propyl disulfide (Pro2S2). Breadmaking properties also were improved in bread prepared from wheat flour blended with Pro2S2 alone. Brabender farinographs of Welsh onion powder/wheat flour and Pro2S2/wheat flour showed interesting properties in modifying the width of the tail. Size‐exclusion high performance liquid chromatography of the wheat proteins in the control and blended flours showed a profile of low, medium, and high molecular weight peaks. The area of the high molecular weight peak was larger in the 2 blended flours than in control, indicating this protein was important for the improvement. 相似文献