ELECTRON GUN FOR LARGE ORBIT GYROTRON (LOG) WITH DECREASED INFLUENCE OF CATHODE PLASMA ON ELECTRON BEAM PROPERTIES

High power Large Orbit Gyrotron (LOG) [1] is now under development at FIR FU. First version of this device was recently manufactured and then assembled with power supply ETIGO-IV [2]. Results of preliminary tests of electron-optic system are presented. The conditions when stable flat form of current pulse realized are discussed. Analytical estimations of cathode-anode distance to achieve small influence of cathode plasma during high voltage (HV) pulse are performed. Two new electron gun versions with decreased influence of the cathode plasma on its impedance and pulse form are suggested and optimized. New optimal magnetic field distributions are found. First gun has quiasi-flat cathode configuration near the anode diaphragm and provides operating current about 60 A. Second one uses blade cathode with operating current about 30 A. Beam quality for both guns is suitable for LOG operation.     

New Paradigms in Wireless Communication Systems

This paper discusses what a new paradigm can be in wireless communication systems of the twenty-first century. First, it suggests two directions for the new paradigm; one is “micro- and nano-device communication system” which is the projected scenario considering that the entities in source and destination have been shrinking throughout the history of wireless communication systems. The second direction is “networked robot system”, which emerges as a natural extension of mobile ad hoc networking where the networking is closely related to motion control of robots. Secondly, it shows two interesting research topics, “the new communication protocol design” and “signal processing”, respectively, that arise in the wake of the fusion between the two directions in the novel communication paradigm. Finally, it considers a new science of wireless communications in the twenty-first century. Shinsuke Hara received the B.Eng., M.Eng. and Ph.D. degrees in communications engineering from Osaka University, Osaka, Japan, in 1985, 1987 and 1990, respectively. From April 1990 to March 1997, he was an assistant professor in the Department of Communication Engineering, School of Engineering, Osaka University, and from October 1997 to September 2005, he was an associate professor in the Department of Electronic, Information and Energy Engineering, Graduate School of Engineering, Osaka University. Since October 2005, he has been a professor in the Department of Physical Electronics and Informatics, Graduate School of Engineering, Osaka City University. In addition, from April 1995 to March 1996, he was a visiting scientist at Telecommunications and Traffic Control Systems Group, Delft University of Technology, Delft, The Netherlands. His research interests include wireless communications systems and digital signal processing. Hiroyuki Yomo received B.S. degree in communication engineering from Department of Communication Engineering, Osaka University, Osaka, Japan, in 1997, and M.S. and Ph.D. degrees in communication engineering from Department of Electronic, Information, and Energy Engineering, Graduate School of Engineering, Osaka University, Osaka Japan, in 1999 and 2002, respectively. From April 2002 to March 2004, he was a Post-doctoral Fellow in Department of Communication Technology, Aalborg University, Denmark. From April 2004 to September 2004, he was at Internet System Laboratory, NEC Corporation, Japan. Since October 2004, he has been an Assistant Research Professor in Center for TeleInfrastructure (CTIF), Aalborg University, Denmark. His main research interests are access technologies, radio resource management, and link-layer techniques in the area of short-range communication, cellular network, cognitive radio, and sensor network. Petar Popovski received the Dipl.-Ing. in electrical engineering and M.Sc. in communication engineering from the Faculty of Electrical Engineering, Sts. Cyril and Methodius University, Skopje, Republic of Macedonia, in 1997 and 2000, respectively. He received a Ph.D. degree from Aalborg University, Denmark, in 2004. From 1998 to 2001 he was a teaching and research assistant at the Institute of Telecommunications, Faculty of Electrical Engineering in Skopje. He is currently Assistant Professor at the Department of Communication Technology at the Aalborg University. His research interests are related to the PHY-MAC aspects of wireless protocols, wireless sensor networks, random access protocols, and network coding. Kazunori Hayashi received the B.E., M.E. and Ph.D. degrees in communication engineering from Osaka University, Osaka, Japan, in 1997, 1999 and 2002, respectively. He spent 3 months in 2000 at Aalborg University, Denmark, as a Visiting Scholar. Since 2002, he has been with the Department of Systems Science, Graduate School of Informatics, Kyoto University. He is currently an Assistant Professor there. His research interests include digital signal processing for communications systems.     

Development of mushrooms for thrombosis prevention by protoplast fusion

With thrombosis a major cause of death in Japan and the Western world, thrombin-inhibitory agents that constrain the formation of fibrin are sought. We screened for basidiomycetes showing anti-thrombin activity and isolated Laetiporus sulphureus. However, it was difficult to cultivate and its form was not satisfactory. We therefore used protoplast fusion between L. sulphureus and the commonly cultivated basidiomycete Hypsizygus marmoreaus to obtain cultivable basidiomycetes that produced an anti-thrombin substance. For the protoplast fusion of L. sulphureus and H. marmoreaus, the protoplast concentration, alternating electric field intensity, dielectrophoresis duration, and field pulse intensity used were of 1 x 10(7) protoplasts/ml, 100 V/cm.1 MHz, 60 s, and 8 kV/cm, respectively. The number of regenerated colonies obtained was 4961, from which 43 strains were selected for electrophoretic analysis. Four of the fusants were found to have a band from each parent in isozyme patterns obtained using their crude extract. The fruiting bodies of the fusants were very similar to those of H. marmoreaus. Crude extract from each of the fusants and from L. sulphureus showed anti-coagulative activity in terms of the thrombin clotting time. We thus obtained improved basidiomycetes that produce an anti-thrombin substance, are easily cultivated, and whose form resembles H. marmoreaus, a commonly used culinary mushroom.     

Efficient transformation of Mesorhizobium huakuii subsp. rengei and Rhizobium species

The transformation of Mesorhizobium huakuii subsp. rengei B3 with either pBBR122 or pKT230 was carried out. We determined the optimal conditions required for transformation by electroporation and obtained up to 10(5) CFU/microg pBBR122. Plasmids prepared from strain B3 yielded higher transformation efficiency than those from various dam or dcm mutant strains of Escherichia coli. This result suggests that a high transformation efficiency is not related to the methylation of plasmid DNA in E. coli. Using the optimal conditions for electroporation, we performed transformation of several species of Rhizobium, Mesorhizobium and Sinorhizobium. All tested strains of these species were transformed with pBBR122. Strains of M. huakuii and R. phaseoli AHU1133 were transformed at high efficiency, whereas transformation efficiencies of Rhizobium sp. NGR234 and S. meliloti strains were less than 2 x 10(3) CFU/microg plasmid DNA.     

Purification and some properties of a chitinase from Xanthomonas sp. strain AK

Chitinase B (ChiB) was purified from the culture supernatant of Xanthomonas sp. strain AK by Phenyl-Toyopearl 650M and DEAE-Toyopearl 650M column chromatographies. The purified enzyme preparation gave a single band on SDS-polyacrylamide gel electrophoresis and the molecular weight of ChiB was estimated to be 48,000. The enzyme was optimally active at pH 6.0 and 60 degrees C. N-Terminal amino acid sequence analysis suggested that ChiB is a member of glycosyl hydrolase family 18 and that it is genetically different from ChiA recently reported (Sakka et al., J. Ferment. Bioeng., 86, 527-533, 1998). Immunological analysis suggested that ChiB was the major chitinase species in the culture supernatant of Xanthomonas sp. strain AK and that production of the enzyme was induced by the presence of chitin.     

Inhibition by drebrin of the actin-bundling activity of brain fascin, a protein localized in filopodia of growth cones

The purification of drebrin, an actin-binding protein that is specifically expressed in embryonic rat brain, was described previously. During the purification of drebrin, we found that an actin-binding protein of 54 kDa was also expressed at high levels in embryonic brain, and this protein was identified by immunoblotting as fascin. To explore the roles of fascin in brain development, we purified fascin from brains of infant rats and characterized it. We found that the actin-binding activity of fascin was strongly inhibited by drebrin. Fascin caused formation of actin bundles, a process that was inhibited in the presence of drebrin, as confirmed by electron microscopy and a low-speed centrifugation assay. In PC12 cells, fascin was localized in the filopodia of growth cones, whereas drebrin was localized in the basal region of growth cones. Our results suggest that fascin might play an important role in the organization of actin in filopodia and that this organization might be regulated by drebrin.     

Bit-dependent degradation caused by stimulated Brillouin scatteringin CPFSK coherent optical repeaterless systems with booster amplifiers

An interesting phenomenon due to stimulated Brillouin scattering (SBS) is experimentally found in a CPFSK heterodyne system with a booster amplifier. We find that the demodulated waveform amplitudes of just a few distinguished bits are strongly suppressed leading to a significant increase in BER. It is confirmed that the BER degradation can be reduced by adjusting the threshold voltage bias of the receiver decision circuit     

Reference values for bisphosphoglycerate mutase protein content and specific activity in human erythrocytes

Cytomegalovirus (CMV) gastritis has been reported in transplant patients. Symptoms are considered nonspecific, and gastroscopy with biopsy is usually performed to establish the diagnosis. Three patients are described here 1 to 3 months after solid organ transplantation, with primary CMV gastritis, confirmed by gastroscopy, histopathologic examination and cultures. The clinical presentation in all three cases was sharp epigastric pain that decreased in a supine position, increased while sitting and further increased when standing or walking. The epigastric pain completely resolved after treatment with ganciclovir. To the best of our knowledge, such postural epigastric pain has not been described as a specific symptom in any other clinical entity and may be a unique sign of primary CMV gastritis.     

Two cases of cerebral aneurysm detected after recanalization of the middle cerebral artery]

Two cases of aneurysm incidentally detected after recanalization of middle cerebral artery (MCA) occlusion are reported. Patient 1 was a 62-year-old male with sudden onset of left hemiparesis. We performed emergent intravascular surgery. The initial cerebral angiography revealed occlusion at the M1 portion of the right MCA. After partial recanalization with a microcatheter, carotid angiography revealed a right M1-M2 junction aneurysm. Due to the risk of aneurysmal rupture, the thrombolytic procedure was stopped. Follow up angiography after 1 month revealed complete recanalization of the right MCA and a persistent aneurysm. Patient 2 was a 65-year-old male with left hemiparesis. The initial cerebral angiography revealed occlusion at the M1 portion of the right MCA. After 1 month follow-up cerebral angiography revealed spontaneous recanalization of the right MCA and an incidental aneurysm at the M1-M2 junction. Neck clipping of the aneurysm was performed. When using a microcatheter or microballoon catheter to treat arterial occlusion, surgeons should consider the possibility of a rupture of a hidden aneurysm.     

Hypertrophic cranial pachymeningitis with spinal epidural granulomatous lesion

A 67-year-old woman with a one-year history of tinnitus and headache had multiple cranial nerve palsies of V, VII, VIII, IX, X, XI and spastic paraparesis. She also had a secretory otitis media. Gd-DTPA-enhanced magnetic resonance imaging (MRI) revealed hypertrophy of the dura of the posterior fossa and spinal epidural mass which extended from C7 to T10. A biopsy of the epidural mass showed chronic granulomatous change. These lesions were completely cured with administration of antibiotics. We believe this case of double-lesion of hypertrophic cranial pachymeningitis and spinal epidural granulomatous lesion originated from a bacterial infection secondary to the secretory otitis media.