Kinetic analysis for effect of initial substrate concentration on growth and secondary metabolite production in cultures of Nicotiana tabacum

Suspension cultures of tobacco cells were studied using airlift and rotary-drum bioreactors. The effect of initial concentrations of a major substrate, sucrose, on the growth and production of a secondary metabolite, phenolic compounds, was investigated. The dry weights and total concentrations of the phenolic compounds increased with the initial sucrose concentration in both bioreactors. Both bioreactors were found to have the same tendency for the effect of initial sucrose concentration. The structured model, presented previously was modified by considering that sucrose was hydrolyzed to glucose and fructose by an enzymatic reaction. The previous and the new models were applied to the above two sets of experimental data obtained with two bioreactors, independently. The hydrolysis of sucrose was elucidated to contribute slightly to the overall kinetics of growth and secondary metabolite production in these cultures. Furthermore, the levels of shear damage in each bioreactor were quantitatively compared based on the death rate constant, k_i, which is one of the model constants.     

Soluble VCAM-1 induces chemotaxis of Jurkat and synovial fluid T cells bearing high affinity very late antigen-4

It has been shown that cells with high affinity very late Ag (VLA)-integrins have up-regulated expression of a beta1-subunit epitope, which is detected by 15/7 mAb. In this study, we demonstrate that soluble VCAM-1 (sVCAM-1) exhibits chemotactic activity of T cells with high affinity VLA-4 against VCAM-1, such as Jurkat T cells and IL-2-dependent T cells. Moreover, we found that T cells in the synovial fluid show high basal migration in the absence of sVCAM-1, compared with peripheral blood T cells in patients with rheumatoid arthritis. Among T cells in the synovial fluid, CD45RO+ memory T cells, in response to sVCAM-1, showed a much higher than basal migratory response when compared with CD45RA+ naive cells, while no significant difference was observed between CD4+ and CD8+ T cells. The chemotactic activity of sVCAM-1 is inhibited in the presence of anti-VCAM-1 and anti-VLA-4, which interfered with the binding between VCAM-1 and VLA-4. Inhibition studies using various kinase inhibitors (C3 exoenzyme, KN62, and H7) show that Rho, Ca2+/calmodulin-dependent kinase II, and protein kinase C are involved in signal transduction in sVCAM-1-induced chemotaxis, respectively, whereas tyrosine kinase seems to play a lesser role, since genistein showed only partial inhibition of T cell chemotaxis. Western blot analysis using an anti-phospho-serine mAb (MO82) reveals that Ser82 in the vimentin is phosphorylated specifically by Ca2+/calmodulin-dependent kinase II through sVCAM-1 activation in the IL-2 dependent T cells. Collectively, by inducing migration and recruitment of T cells through several kinase activations, sVCAM-1 contributes to the development of the inflammation of synovial lesion.     

Preparation of plastic spherical microlenses by use of a fluoropolymer stencil and oil-bath heating

A new method for fabricating plastic spherical microlenses was developed, which allowed self-alignment of lenses and self-organized formation of a spherical shape. First a low-surface-energy fluoropolymer thin film was deposited and patterned as a stencil. Then photosensitive phenol resin was patterned on it as the lens material. Finally the resin was annealed in an oil bath to form a sphere. The molten phenol resin spontaneously formed a sphere and positioned itself in the center of the fluoropolymer ring pattern as a result of the difference of surface free energy and the equivalently zero-gravity condition in the oil bath. When a light-emitting-diode printer head was loaded with spherical microlenses, its optical output increased by 1 order of magnitude.     

Expression of 5-lipoxygenase and 5-lipoxygenase-activating protein mRNAs in the peripheral blood leukocytes of asthmatics

Hormone-sensitive lipase (HSL) catalyzes the rate-limiting step in adipocyte lipolysis. We have studied the effect of glucose and long chain fatty acids on the HSL mRNA content of 3T3-F442A adipocytes. Exposure of the cells for 32 h to a medium without glucose led to a decrease by a factor of 2.5-3 in the HSL mRNA without a change in C/EBP alpha mRNA or triglyceride content of the adipocytes. The reduction in HSL mRNA level was accompanied by a decrease in HSL total activity. The effect of glucose exposure was observed after 24 h of exposure and was reversible. Treatment of the adipocytes with oleate did not affect HSL expression. These data show that glucose modulates HSL gene expression and hence could participate in the regulation of adipose tissue lipolysis.     

Time‐frequency analysis of a pressure wave caused by impulse tree using wavelet transform

This paper describes results of time‐frequency analysis of a pressure wave caused by impulse tree extension using wavelet transform. Pressure waves were measured by a piezo sensor which was located on the back of the plane electrode when high‐voltage nanosecond pulses were applied to a point electrode in a low‐density polyethylene block. Frequency of the pressure wave from induced charges on the plane electrode was higher than that of the pressure wave from tree. In addition, the frequency of the pressure wave from tree tended to decrease with increasing gap length because of the dispersion of the pressure wave during its propagation. When a large tree extension occurred between a 5‐mm gap, pressure waves of about 10 MHz propagated from the tree tip and a pressure wave of 1 MHz propagated from the tree stem. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 142(1): 1–7, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10097     

Effects of secretin and cholecystokinin on abdominal blood circulation in unanesthetized rat (microsphere method)]

Mucous barrier was searched by the histochemical method of mucopolysaccharides and by the measurement of precipitated mucus of gastric juice. The neutral polysaccharide stored within the surface epithelial cells must be a source of the mucus of the gastric juice. The storage of the polysaccaride was decreased by a long-term stimulation by histamine, and the precipitated mucus volume was also decreased shortly after the stimulation. Therefore, some kind of the stimulation for the gastric secretion must be avoided for prevention of peptic ulcer. The oral administration of the sulfuric polysaccharide extracted from seaweed prevented the occurrence of experimental ulcer. It may be concluded that the exogeneous polysaccaride can take the place of the endogenous polysaccharide.     

Basic study of aerial flashover characteristics generated from pore of insulating solid

This paper reports a study on the possibility of an aerial flashover between a coil conductor and a casing in rotating machines under the application of a lower voltage than Paschen's voltage, even when enough insulation distance is secured. The time lag to aerial flashover originating from surface flashover was measured. To understand the aerial flashover influenced by the parameters of the voltage application circuit, the aerial flashover distance was measured using a cable which had a simulated pore to confirm the above issue. The surface flashover characteristic was also measured using a photomultiplier tube (PMT). It became clear that aerial flashover occurred a few milliseconds after surface flashover generation. After showing the peak, the aerial flashover distance decreased with increasing time constant. The surface flashover time estimated by the PMT output exhibited different values with change of capacitance when the time constant is larger. On the other hand, the average surface flashover current was almost the same in spite of the change of capacitance. From these results, it was concluded that the aerial flashover distance was influenced by the time constant of the circuit. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 180(3): 9–17, 2012; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21295     

Transient phenomena of current and field distortion due to dynamics of packet‐like charges in LDPE films

Simultaneous measurements of space charge and external current were carried out using a PEA measurement system with an electrometer on the back of a grounding electrode in order to clarify the physical situation of a huge packet of positive space charges in LDPE films. A large number of positive charges from a semiconducting anode were accumulated at the interface between LDPE and an Al‐cathode at a mean applied field of 1.5 MV/cm and then finally disappeared. The results of simultaneous measurements showed that the external current kept a relatively high value during charge accumulation and further increased when the charges disappeared. Both the charge dynamics and the external current were restricted by addition of a low‐molecular‐weight paraffin wax, indicating that carrier transport was influenced by the microstructure of the polymer. The dynamics of the residual charges after short‐circuiting is also discussed. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 179(4): 10–17, 2012; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21256     

Boson peak and structural heterogeneity in ternary SiO2-Al2O3-B2O3 glasses

We use low-temperature heat capacity, low-frequency Raman scattering, and THz time domain spectroscopy in order to scale the vibrational density of states and the Boson peak in SiO₂-Al₂O₃-B₂O₃ Yb-laser host glasses. When substituting B₂O₃ for SiO₂ at constant Al₂O₃ dopant level, we find an optimal value for the ratio of B/Al in terms of mixture stability, at which the excess in the electron donor capability of Al₂O₃ (relative to the SiO₂ backbone) is compensated by the more acidic B₂O₃. At this composition, Al₂O₃ plays a mediating role in the structure of aluminoborosilicate glasses, facilitating dissolution of Yb₂O₃ and admixture of B₂O₃ into the SiO₂ network.