Performance Test of CW 300 GHz Gyrotron FU CW I

A 300 GHz CW gyrotron FU CW I has been developed and installed in the Research Center for Development of Far-Infrared Region, University of Fukui as a power source of a high frequency material processing system. Its performance was tested and the maximum power of 1.75 kW / CW has been attained at the beam voltage of 15 kV and the beam current of 1A. The maximum window power efficiency of 15.5% has been obtained at the cathode voltage slightly lower than 15 kV. This gyrotron is designed to deliver a Gaussian beam after mode conversion from the oscillation mode TE_22,8 in the cavity with a complex of an internal radiator and beam shaping mirrors. The detailed measurement with an infrared camera has confirmed that a Gaussian beam is radiated when the magnetic field strength B _c at the cavity is adjusted at a proper value. However, within a range of B _c , the output power is emerged into multiple directions, which suggests simultaneous oscillation of competing cavity modes.     

In vivo protein delivery to human liver-derived cells using hepatitis B virus envelope pre-S region

Human hepatocyte-specific delivery of green fluorescent protein was succeeded in the mouse xenograft model by fusion with hepatitis B virus surface antigen pre-S regions (pre-S(1+2)), not with each pre-S region. The entire pre-S region would be useful for human liver-specific delivery of therapeutic proteins and bio-imaging fluoroproteins in biomedical field.     

Calcitonin receptor binding properties in bone and kidney of the chicken during the oviposition cycle

The binding property of calcitonin (CT) in the membrane fraction of calvaria and kidney of egg-laying and nonlaying hens was analyzed using a [125I] CT binding assay system. Binding properties of CT receptors in both tissues satisfy the authentic criteria of a receptor-ligand interaction in terms of specificity, reversibility, and saturation. Scatchard plots revealed a single class of binding sites. Values of the equilibrium dissociation constant (Kd) and binding capacity (Bmax) in laying hens showed a decrease during the period between 3 h before and 2 h after oviposition. No change was observed in nonlaying hens. In vivo administration of 17beta-estradiol or progesterone caused the decrease in Kd and Bmax values. The results suggest that the binding affinity and capacity of the CT receptor in the calvaria and the kidney of the hen may be modulated by the ovarian steroid hormone.     

Growth characteristics in the initial stage of micrometastasis formation by bacterial LacZ gene-tagged rat prostatic adenocarcinoma cells

In a previous study we observed that protein tyrosine phosphorylation was significantly diminished in the focal adhesions of human fibroblasts attached on a hydrophobic surface in comparison with hydrophilic glass. This result raises the possibility that the tyrosine phosphorylation pathway may be involved in the regulation of cell-biomaterial interaction. To learn more about the interaction of anchorage-dependent cells with biomaterials, four different materials with wettability ranging from hydrophilic (water contact angle 25 degrees) to hydrophobic (water contact angle 111 degrees) were investigated, i.e. clean glass (glass), aminopropylsilane (APS), octadecylsilane (ODS) and silicone (SI). Immunofluorescence microscopy revealed increased stress formation and fibronectin (FN) receptor-rich focal adhesions for fibroblasts attached on more hydrophilic surfaces (glass and APS) in comparison to the relatively hydrophobic materials (ODS and SI). Phosphorylation of tyrosine residues, also studied by immunofluorescence microscopy, was considerably higher on glass and APS, lower for ODS, negligible for SI, and was found to colocalize with FN receptor-rich focal adhesions. Preadsorption of FN tended to restore cell adhesion and spreading on the hydrophobic ODS and SI. Quantitative data on cell proliferation and tyrosine phosphorylation showed moderate wettable material maximum values for APS, followed by glass. ODS and SI, demonstrating a non-linearity of these parameters with the wettability of materials. Interestingly, the preadsorption of FN increased both parameters, particularly for the hydrophobic materials ODS and SI. Phosphorylation of tyrosine on FN-coated substrata was corroborated by the accessibility of binding sites estimated by ELISA using polyclonal and monoclonal FN antibodies. Our results suggest that measurement of the phosphotyrosine activity of cells may be a sensitive parameter for the ability of biomaterials to support the attachment and proliferation of cells.     

The MSG1 and AXR1 genes of Arabidopsis are likely to act independently in growth-curvature responses of hypocotyls

Growth-curvature responses of hypocotyls of Arabidopsis thaliana (L.) Heynh. were measured in double mutants between msg1 and axr1, both of which are auxin-resistant and defective in hypocotyl growth curvature induced upon unilateral application of auxin. The msg1 axr1 double mutants showed no auxin-induced growth curvature, that is, they exhibited the msg1 phenotype, though the axr1 defects were partial. Hypocotyls of both the msg1 and axr1 mutants were partially defective in second-positive phototropism, whereas the double mutants lost the response completely. When grown on vertically held agar plates, the axr1 mutant showed normal hypocotyl gravitropism and the mutation did not affect the reduced hypocotyl gravitropism of msg1. Hypocotyls of msg1 and axr1 mutants grew upward like wild-type ones when grown along an agar surface, while they grew more randomly when grown without an agar support, suggesting that axr1 hypocotyls are not completely normal in gravitropism. The extent of defects in growth orientation increased in the order: msg1 axr1 double mutants > msg1 > axr1 > wild type. The hypocotyls of these mutants showed auxin resistance in the order: msg1 axr1 > axr1 > msg1 > wild type. The msg1 mutant had epinastic leaves and axr1 had wrinkled leaves; leaves of the msg1 axr1 double mutants were epinastic and wrinkled. These results suggest that MSG1 and AXR1 act independently in separate pathways of the reactions tested in the present study. In contrast, the phenotype of the msg1 aux1 double mutants shows that AUX1 is not significantly involved in these phenomena.     

Estimation of charge distribution on a bulky solid dielectric using regularization technique

We have been studying a multi‐point charge measurement method using an electrostatic probe. In this technique, charge densities x must be estimated from the probe outputs b by an inverse calculation based on an equation A x = b . The matrix A is obtained by applying a numerical field calculation technique. When the matrix A is in ill‐condition, the solution often makes no sense, including extremely large errors. Therefore, we apply the regularized least squares method (RLS) with a penalty term to perform the inverse calculation stably for the ill‐conditioned matrix. The penalty term imposes some constraints on the solutions. In this paper, first, we have analyzed the accuracy of the charge distribution estimated by the inverse calculation. Although the perturbation bound of the solution errors has already been proposed for the least squares method, it has not yet been given for the RLS. We have derived the equations that express the perturbation bound of the solution errors in applying the RLS to evaluate the estimation accuracy. Second, we have applied the above equations to an experimental result for a cylindrical dielectric solid, and estimated the charge distribution represented by 10,140 unknowns. We have utilized an iteration technique and the symmetric configuration of the measured arrangement so as to reduce the amount of operations and memory capacity required for the inverse calculation. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 163(2): 1–13, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20412     

Rare occurrence of ras and p53 gene mutations in mouse stomach tumors induced by N-methyl-N-nitrosourea

BACKGROUND: For evaluating pancreaticobiliary stenoses during endoscopic retrograde cholangiopancreatography (ERCP) tissue sampling techniques may be important. Brush cytology and forceps biopsy during ERCP are two potential, but so far only incompletely evaluated, tools for the diagnosis of malignant biliary or pancreatic stenoses. METHODS: Between 1992 and 1995 we acquired 133 cytologic and/or histologic samples from 119 patients who underwent ERCP because of biliary duct stenoses. Sixteen patients had to be excluded from the study due to insufficient follow-up information. After papillotomy, brush cytology was performed in 65 cases (63 patients), and forceps biopsy in 119 cases (106 patients under fluoroscopic guidance. Both methods were applied in combination 51 times (48 patients). The nature of the stenoses was confirmed by surgery, autopsy, or by the subsequent clinical course. RESULTS: The sensitivity was 46.7% for brush cytology and 64.9% for forceps biopsy. The combined application of both methods resulted in superior sensitivity (70.4%). Specificity was 100% for all methods. CONCLUSIONS: These numbers lead us to recommend a combined and more frequent application of brush cytology and forceps biopsy of bile duct stenoses to enhance the diagnostic yield whenever substantial influence on therapy can be expected.     

Simultaneous Stabilization of Gyrotron Frequency and Power by PID Double Feedback Control on the Acceleration and Anode Voltages

In this paper, we present the results of simultaneous stabilization of both the frequency and the output power by a double PID feedback control on the acceleration and anode voltages in the 460-GHz gyrotron FU CW GVI, also known as “Gyrotron FU CW GO-1” (according to the nomenclature adopted at Osaka University). The approach used in the experiments is based on the modulation of the cyclotron frequency and the pitch factor (velocity ratio) of the electron beam by varying the acceleration and the anode voltages, respectively. In a long-term experiment, the frequency and power stabilities were made to be better than ±10^?6 and ±1%, respectively.