277 research outputs found
Ontogenetic changes of the water status and accumulated soluble compounds in developing and ripening mume (Prunus mume) fruit measured by 1H-NMR analysis
The physiological changes of intact mume (Prunus mume Sieb. et Zucc. cv. Rinshu) fruit tissues were examined by measuring the physical states of cell-associated water in the fruit tissues with developing and ripening using 1H-NMR spectroscopy. We found that the water molecules in mume fruit tissues existed in several different compartments with different mobilities. Additionally, spectral recovery in the water proton indicated reverse relationships between the pericarps and seeds at the immature and mature stages. In the pericarp tissues, the longest T1 and longer T2 markedly increased, while those in the seeds decreased. From these results, the change in the water status with growth stage had reverse trajectories in the pericarp and seed of the fruit. In the pericarp tissues, both water uptake and dry weight prominently increased with ripening. The epidermis and inner parenchymal cells of the pericarp tissues remarkably enlarged as a sigmoidal growth curve. Membrane permeability, indicating a loss of membrane integrity, increased in the pericarp tissues. The elongation in the fully vacuolated cells and changes in the membrane permeability in the pericarp tissues with ripening correlated to the longest T1. In contrast, the high mobility of water in the seeds began to decrease with maturation, while oil began to accumulate. Thus, the mobility of water, as analyzed in this study, is considered to reflect the results of physiological changes such as cellular heterogeneity and spatial arrangements both in the pericarp and in seed tissues for mume fruit with development and ripening
Dynamics vs electronic states of vortex core of high-T_c superconductors investigated by high-frequency impedance measurement
Dynamics of vortices reflects the electronic states of quasiparticles in the
core. To understand this, we investigated the following three issues. (1) We
investigated the complex surface impedance, Zs, of YBa2Cu3Oy as a function of
magnetic field, H. The total features were well expressed by the Coffey-Clem
model. From the data, we estimated the viscosity and pinning frequency, which
were found to be independent of frequency. In particular, the obtained
viscosity definitely shows that the core of vortex of YBa2Cu3Oy is moderately
clean. This result suggests that new physics will show up, for the physics of
quantum moderately clean vortex core is unknown at all. (2) An anomaly found in
the surface reactance at the first order transition (FOT) of vortex lattice was
investigated in Bi2Sr2CaCu2Oy with various doping levels. As a result, the
anomaly was found only in the samples exhibiting the FOT. On the other hand, we
did not observe the anomaly in YBa2Cu3Oy. These suggest that the anomaly is due
to the change in the electronic states of the vortices characteristic of
materials with very strong anisotropy. (3) We measured H dependence of both the
thermal conductivity \kappa(H) and Zs(H) in exactly the same pieces of crystal.
We could not find any anomaly in Zs(H) even at the onset of the plateau. This
result suggests that the origin of the plateau in \kappa(H) is not a drastic
phase transition but is rather gradual crossover.Comment: 6 pages, 5 figures, Proceedings of Plasma2000(Sendai), to be
published in Physica
Fluorescence multispectral imaging-based diagnostic system for atherosclerosis
Background: Composition of atherosclerotic arterial walls is rich in lipids such as cholesterol, unlike normal arterial walls. In this study, we aimed to utilize this difference to diagnose atherosclerosis via multispectral fluorescence imaging, which allows for identification of fluorescence originating from the substance in the arterial wall. Methods: The inner surface of extracted arteries (rabbit abdominal aorta, human coronary artery) was illuminated by 405 nm excitation light and multispectral fluorescence images were obtained. Pathological examination of human coronary artery samples were carried out and thickness of arteries were calculated by measuring combined media and intima thickness. Results: The fluorescence spectra in atherosclerotic sites were different from those in normal sites. Multiple regions of interest (ROI) were selected within each sample and a ratio between two fluorescence intensity differences (where each intensity difference is calculated between an identifier wavelength and a base wavelength) from each ROI was determined, allowing for discrimination of atherosclerotic sites. Fluorescence intensity and thickness of artery were found to be significantly correlated. Conclusions: These results indicate that multispectral fluorescence imaging provides qualitative and quantitative evaluations of atherosclerosis and is therefore a viable method of diagnosing the disease
Atomic-scale visualization of initial growth of homoepitaxial SrTiO3 thin film on an atomically ordered substrate
The initial homoepitaxial growth of SrTiO3 on a (\surd13\times\surd13) -
R33.7{\deg}SrTiO3(001) substrate surface, which can be prepared under oxide
growth conditions, is atomically resolved by scanning tunneling microscopy. The
identical (\surd13\times\surd13) atomic structure is clearly visualized on the
deposited SrTiO3 film surface as well as on the substrate. This result
indicates the transfer of the topmost Ti-rich (\surd13\times\surd13) structure
to the film surface and atomic-scale coherent epitaxy at the film/substrate
interface. Such atomically ordered SrTiO3 substrates can be applied to the
fabrication of atom-by-atom controlled oxide epitaxial films and
heterostructures
Real space imaging of the metal - insulator phase separation in the band width controlled organic Mott system -(BEDT-TTF)Cu[N(CN)]Br
Systematic investigation of the electronic phase separation on macroscopic
scale is reported in the organic Mott system
-(BEDT-TTF)Cu[N(CN)]Br. Real space imaging of the phase
separation is obtained by means of scanning micro-region infrared spectroscopy
using the synchrotron radiation. The phase separation appears near the Mott
boundary and changes its metal-insulator fraction with the substitution ratio
in
-[(-BEDT-TTF)(-BEDT-TTF)]Cu[N(CN)]Br,
of which band width is controlled by the substitution ratio between the
hydrogenated BEDT-TTF molecule (-BEDT-TTF) and the deuterated one
(-BEDT-TTF). The phase separation phenomenon observed in this class of
organics is considered on the basis of the strongly correlated electronic phase
diagram with the first order Mott transition.Comment: 10 pages, 8 figure
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