Changes in the activity and abundance of NADPH:protochlorophyllide oxidoreductase (NPR) and the abundance of mRNA encoding it were examined during the greening of 5-d-old etiolated cucumber cotyledons under continuous illumination. To measure NPR activity in the extracts from fully greened tissues, we have developed an improved method of assay. Upon exposure of etiolated cotyledons to light, NPR activity decreased rapidly within the first 2 h of exposure. Thereafter, enzymatic activity increased transiently, reaching a submaximum level at 12 h, and decreased slowly. The level of immunodetectable NPR protein followed the same pattern of changes during 96 h of greening as observed for NPR activity. The NPR mRNA in etiolated cotyledons disappeared quickly in the 1st h of irradiation. However, the level of mRNA increased thereafter to reach 3-fold or more of the dark level at 12 h and then decreased. The changes in the activity, protein level, and mRNA level after the first rapid decreases corresponded chronologically and nearly paralleled the increase in the rate of chlorophyll accumulation. These findings suggest that the greening of cucumber cotyledons is regulated basically by the level of NPR protein without activation or repression of enzymatic activity and that NPR mRNA increased by light maintains the level of enzyme protein necessary for greening.
We have successfully fabricated x(0.65PMN-0.35PT)–(1 − x)PZT (xPMN-PT–(1 − x)PZT), where x is 0.1, 0.3, 0.5, 0.7 and 0.9, thick films with a thickness of approximately 9 µm on platinized silicon substrate by employing a composite sol–gel technique. X-ray diffraction analysis and scanning electron microscopy revealed that these films are dense and creak-free with well-crystallized perovskite phase in the whole composition range. The dielectric constant can be controllably adjusted by using different compositions. Higher PZT content of xPMN-PT–(1 − x)PZT films show better ferroelectric properties. A representative 0.9PMN-PT–0.1PZT thick film transducer is built. It has 200 MHz center frequency with a −6 dB bandwidth of 38% (76 MHz). The measured two-way insertion loss is 65 dB.
Background and Aims: Shear wave elastography is a potential method for evaluating peripheral neuropathy, but lacking reference values. The aim of this study was to measure tibial nerve stiffness in healthy individuals using shear wave elastography and to investigate the influencing factors of tibial nerve stiffness.Methods: Shear wave elastography of bilateral tibial nerves was performed in 50 healthy individuals 4 cm proximal to the medial malleolus. Mean shear modulus data of tibial nerves were obtained and recorded. Intra-and interobserver agreement were assessed using intraclass correlation coefficients. Differences among groups (grouped by laterality, sex, age, and body mass index) were analyzed with independent-samples t-tests and paired t-tests. Effect size (Cohen's d) was also calculated.
Results:The intra-and interobserver agreement were moderate (intraclass correlation coefficient, 0.700-0.747) for all participants, and was poor (intraclass correlation coefficient, 0.265-0.088) in very thin people (body mass index <18.5 kg/m 2 ). The shear wave elastography measurements of the tibial nerve did not show a significant difference between legs, sexes, or different age groups.Higher values of tibial nerve stiffness were found in thinner participants.Conclusions: Shear wave elastography is a method to evaluate the stiffness of peripheral nerves. The measurement results were likely influenced by body mass index of the participants.
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