Ionic diffusion and structural changes in lithium compounds

⁷Li NMR measurements have been performed to study milling effects on ionic diffusion in lithium cobalt oxide, LiCoO₂ and piezoelectric compound, LiNbO₃ prepared by mechanical milling method. The milling process gives quite different effects on NMR spectra of these compounds. Both ⁷Li MAS and static NMR spectra of the milled LiCoO₂ show the line broadening with increasing milling time. ⁵⁹Co static spectra also show specific changes in the line shape with increasing milling time. These results would be attributed to the change in an electronic state of Co 3d orbitals because of charge compensation associated with oxygen vacancies and/or defects. ⁷Li static NMR spectrum of milled LiNbO₃ shows complicated line shape with increasing milling time. It is explained by superposition of two spectra arising from mobile Li⁺ ions and non-mobile ones settled on the fixed site. It is shown that the ratio of mobile Li⁺ ions increases up to a maximum of 9.4% with increasing milling time. Milling effects on the Li⁺ ionic diffusion in LiCoO₂ and LiNbO₃ are discussed in connection with changes in local structure.     

Diffusion-weighted magnetic resonance imaging of human skeletal muscles: gender-, age- and muscle-related differences in apparent diffusion coefficient

Purpose

To evaluate the apparent diffusion coefficient (ADC) of skeletal muscle based on signal intensity (SI) attenuation vs. increasing b values and to determine ADC differences in skeletal muscles between genders, age groups and muscles.

Materials and Methods

Diffusion-weighted images (b values in the range of 0–750 s/mm² at increments of 50 s/mm²) of the ankle dorsiflexors (116 subjects) and the erector spinae muscles (86 subjects) were acquired with a 1.5-T MR device. From the two different slopes obtained in SI vs. b-value logarithmic plots, ADC^b0–50 (b values=0 and 50 s/mm²) reflected diffusion and perfusion, while ADC^b50–750 (b values in the range of 50–750 s/mm² at increments of 50 s/mm²) approximated the true diffusion coefficient. Moreover, to evaluate whether this b-value combination is appropriate for assessing the flow component within muscles, diffusion-weighted images of the ankle dorsiflexors (10 subjects) were obtained before and during temporal arterial occlusion.

Results

ADC^b0–50 and ADC^b50–750 were found to be 2.64×10^–3 and 1.44×10^–3 mm²/s in the ankle dorsiflexors, and 3.02×10^–3 and 1.49×10^–3 mm²/s in the erector spinae muscles, respectively. ADC^b0–50 was significantly higher than ADC^b50–750 in each muscle (P<.01). The erector spinae muscles showed significantly higher ADC values than the ankle dorsiflexors (P<.01). However, for each muscle, there were few significant gender- and age-related ADC differences. Following temporal occlusion, ADC^b0–50 of the ankle dorsiflexors decreased significantly from 2.49 to 1.6×10^–3 mm²/s (P<.01); however, ADC^b50–750 showed no significant change.

Conclusion

Based on the SI attenuation pattern, muscle ADC could be divided into ADC that reflects both diffusion and perfusion, and ADC that approximates a true diffusion coefficient. There were significant differences in ADC of functionally distinct muscles. However, we barely found any gender- or age-related ADC differences for each muscle.     

Raman study on electrochemical lithium insertion into multiwalled carbon nanotubes

We have carried out in situ Raman studies during the electrochemical insertion of lithium ions (Li⁺) into pristine and thermally treated multiwalled carbon nanotubes (MWNTs). We found an improved structural integrity as well as the removal of defects in the thermally treated tubes. The different Li⁺ insertion behaviors above 0.5 V in as‐grown and thermally treated tubes could be explained by the presence of defects on the outer surface of the tubes. No change of Raman spectra from 2.8 to 0.8 V is characterized by the coverage of Li⁺ on the outer surface of tubes, whereas the upshift of G band and the absence of a separated G band below 0.75 V indicate the formation of diluted graphite intercalation below the stage‐2 phase (LiC₁₂). Copyright © 2008 John Wiley & Sons, Ltd.     

Cryopreservation and metabolic profiling analysis of Arabidopsis T87 suspension-cultured cells

We established a simple cryopreservation protocol for Arabidopsis T87 cells using an encapsulation-dehydration method. T87 cells were encapsulated into alginate beads containing 2 M glycerol and 0.4 M sucrose. Alginate beads containing T87 cells were dehydrated with silica gel for 2 h (to c. 0.7 g water per g dry weight followed by immersed in LN. After rewarming at 35 degree C for 3 min and 1-d incubation under continuous illumination at 22 degree C, cryopreserved T87 cells exhibited considerable regrowth. Exponentially-grown 7-d-old T87 cells regrew more vigorously (86% of control) than 14-d-old cells after cryopreservation without preculture in medium containing 0.3 M sucrose. Genetic stability of cryopreserved T87 cells was demonstrated by gas chromatography time-of-flight mass spectrometry (GC-TOF-MS) and principal component analysis (PCA). Transformed T87 cells were cryopreserved using established protocols, and GUS expression was maintained within a 2-fold variance. These results indicate that cryopreservation of T87 cells is useful for comprehensive metabolomics research and for the large scale collection of transformed cultured cell lines for functional genomics research.     

Cryopreservation of black chokeberry in vitro shoot apices

In vitro shoot apices of black chokeberry (Aronia melanocarpa Elliott) were successfully cryopreserved utilizing three methods, namely vitrification, encapsulation-vitrification and encapsulation-dehydration. Encapsulation-dehydration and encapsulation-vitrification, however, seem preferable to vitrification, since the highest respective survival levels of apices (71.1 +/- 2.2 percent and 77.8 +/- 4.4 percent) by both methods were higher than that (60.0 +/- 3.9 percent) by vitrification. In encapsulation-dehydration, the highest survival was achieved when the moisture content of beads was reduced to 19 percent by drying with silica gel for 6 h. In the present study, it was shown that adding 1.0 M glycerol to beads and loading solution during encapsulation-dehydration resulted in high survival (91.7 - 95.0 percent) regardless of lines and polyploids of black chokeberry.     

Search for a stochastic background of 100-MHz gravitational waves with laser interferometers

This Letter reports the results of a search for a stochastic background of gravitational waves (GW) at 100 MHz by laser interferometry. We have developed a GW detector, which is a pair of 75-cm baseline synchronous recycling (resonant recycling) interferometers. Each interferometer has a strain sensitivity of approximately 10;{-16} Hz;{-1/2} at 100 MHz. By cross-correlating the outputs of the two interferometers within 1000 seconds, we found h{100};{2}Omega_{gw}<6 x 10;{25} to be an upper limit on the energy density spectrum of the GW background in a 2-kHz bandwidth around 100 MHz, where a flat spectrum is assumed.     

Effects of ultrasound on apoptosis induced by anti-CD20 antibody in CD20-positive B lymphoma cells

AIM: The present study was conducted to examine the thermal and non-thermal effects of ultrasound on apoptosis induced by anti-CD20 monoclonal antibody (rituximab). MATERIALS AND METHODS: SU-DHL-4 cells, a CD20-positive cell line derived from B cell lymphomas with a BCL2 gene rearrangement, were exposed to continuous 1 MHz ultrasound for therapeutic use under an air- or CO(2)-saturated condition to control cavitation. Early apoptosis (EA) and secondary necrosis (SN) were examined by flow cytometry. Cavitation was determined by detecting the hydroxyl radicals derived from pyrolysis of water molecules using electron paramagnetic resonance-spin trapping. To assess thermal effects, cells were treated in a temperature-controlled water bath. RESULTS: There was a significant additive increase in EA and EA+SN observed in cells treated with rituximab combined with heat at 42 degrees C or non-thermal ultrasound at 0.5 W/cm(2) under an air-saturated condition, where heat or ultrasound induced some cell death. A significant synergistic increase in EA and EA+SN was observed in cells treated with rituximab and ultrasound at 2.5 W/cm(2) under CO(2)-saturated conditions, where inertial cavitations were completely suppressed. No enhancement was observed at a temperature less than 40 degrees C or ultrasound at 0.5 W/cm(2) under CO(2)-saturated conditions. CONCLUSION: These results suggest that the immuno-therapeutic application of ultrasound at relatively high-intensities combined with rituximab thus produces synergistic effects under conditions where the non-thermal and non-cavitational effects are predominant.     

Uniqueness and nonuniqueness of static black holes in higher dimensions

We prove a uniqueness theorem for asymptotically flat static charged dilaton black-hole solutions in higher-dimensional space-times. We also construct infinitely many nonasymptotically flat regular static black holes on the same space-time manifold with the same spherical topology. An application to the uniqueness of a class of flat p-branes is also given.