183 research outputs found
Spread spectrum mobile communication experiment using ETS-V satellite
The spread spectrum technique is attractive for application to mobile satellite communications, because of its random access capability, immunity to inter-system interference, and robustness to overloading. A novel direct sequence spread spectrum communication equipment is developed for land mobile satellite applications. The equipment is developed based on a matched filter technique to improve the initial acquisition performance. The data rate is 2.4 kilobits per sec. and the PN clock rate is 2.4552 mega-Hz. This equipment also has a function of measuring the multipath delay profile of land mobile satellite channel, making use of a correlation property of a PN code. This paper gives an outline of the equipment and the field test results with ETS-V satellite
Recent Status of Small Satellite Study in Japan
This paper describes the recent status of small satellite study in Japan focusing on the activities of the Small Payload WorkShop (SPWS) which was established in January, 1990. The objectives of SPWS are to review the development of small satellite and its launching system, to study the possible mission, to exchange information, to pick up and study the issues to be solved and to contribute to the good and efficient development of the future plan of small satellite utilization in Japan. The discussion to initiate the SPWS is reviewed briefly. The paper describes the recent studies of small satellites missions and launching systems as well as the Japanese small satellites which have been launched so far
Measurement of multipath delay profile in land mobile satellite channels
Mobile satellite communication channel has been evaluated mainly with fading statistics of signal. When bandwidth of transmitting signal becomes wider, frequency selectivity of fading becomes a significant factor of the channel. Channel characteristics, not only signal variation but multipath delay spread should be evaluated. A multipath measurement system is proposed and developed for mobile satellite applications. With this system and ETS-V satellite, multipath delay profiles are measured in various environments including Tokyo metropolis and Sapporo city at 1.5 GHz. Results show that the maximum excess delay is within 1 microsec and the maximum delay spread is 0.2 microsecs at elevation angles of 40 to 47 degrees. In wideband signal transmission of about 1 MHz and more, designers should consider the effect of selective fading due to the multipath of land mobile satellite channel
Bioluminescence Microscopy: Design and Applications
Bioluminescence imaging by microscopy is performed using an ultra-low-light imaging camera. Although imaging devices such as sensor and camera have been greatly improved over time, such improvements have not been attained commercially which are available for microscopes now. We previously optimized the optical system of a microscope for bioluminescence imaging using a short-focal-length imaging lens and evaluated this system with a conventional color charge-coupled device camera. Here, we describe the concept of bioluminescence microscope design using a short-focal-length imaging lens and some representative applications, including intracellular calcium imaging, imaging of clock gene promoter assays, and three-dimensional reconstruction of Drosophila larva. This system facilitates the acquisition of bioluminescence images of single live cells using luciferase, which is similar to fluorescence microscopy using a fluorescent protein
Association of serum magnesium with neurological outcomes in patients who underwent targeted temperature management after cardiac arrest
Transcriptome map of plant mitochondria reveals islands of unexpected transcribed regions
<p>Abstract</p> <p>Background</p> <p>Plant mitochondria contain a relatively large amount of genetic information, suggesting that their functional regulation may not be as straightforward as that of metazoans. We used a genomic tiling array to draw a transcriptomic atlas of <it>Oryza sativa japonica </it>(rice) mitochondria, which was predicted to be approximately 490-kb long.</p> <p>Results</p> <p>Whereas statistical analysis verified the transcription of all previously known functional genes such as the ones related to oxidative phosphorylation, a similar extent of RNA expression was frequently observed in the inter-genic regions where none of the previously annotated genes are located. The newly identified open reading frames (ORFs) predicted in these transcribed inter-genic regions were generally not conserved among flowering plant species, suggesting that these ORFs did not play a role in mitochondrial principal functions. We also identified two partial fragments of retrotransposon sequences as being transcribed in rice mitochondria.</p> <p>Conclusion</p> <p>The present study indicated the previously unexpected complexity of plant mitochondrial RNA metabolism. Our transcriptomic data (<it>Oryza sativa </it>Mitochondrial rna Expression Server: OsMES) is publicly accessible at [<url>http://bioinf.mind.meiji.ac.jp/cgi-bin/gbrowse/OsMes/#search</url>].</p
Thermal-noise-limited underground interferometer CLIO
We report on the current status of CLIO (Cryogenic Laser Interferometer
Observatory), which is a prototype interferometer for LCGT (Large Scale
Cryogenic Gravitational-Wave Telescope). LCGT is a Japanese next-generation
interferometric gravitational wave detector featuring the use of cryogenic
mirrors and a quiet underground site. The main purpose of CLIO is to
demonstrate a reduction of the mirror thermal noise by cooling the sapphire
mirrors. CLIO is located in an underground site of the Kamioka mine, 1000 m
deep from the mountain top, to verify its advantages. After a few years of
commissioning work, we have achieved a thermal-noise-limited sensitivity at
room temperature. One of the main results of noise hunting was the elimination
of thermal noise caused by a conductive coil-holder coupled with a pendulum
through magnets.Comment: 10 pages, 6 figures, Proceedings of the 8th Edoardo Amaldi Conference
on Gravitational Wave
Reduction of thermal fluctuations in a cryogenic laser interferometric gravitational wave detector
The thermal fluctuation of mirror surfaces is the fundamental limitation for
interferometric gravitational wave (GW) detectors. Here, we experimentally
demonstrate for the first time a reduction in a mirror's thermal fluctuation in
a GW detector with sapphire mirrors from the Cryogenic Laser Interferometer
Observatory at 17\,K and 18\,K. The detector sensitivity, which was limited by
the mirror's thermal fluctuation at room temperature, was improved in the
frequency range of 90\,Hz to 240\,Hz by cooling the mirrors. The improved
sensitivity reached a maximum of at 165\,Hz.Comment: Accepted for publication in Physical Review Letters, 5 pages, 2
figure
Functional Fv fragment of an antibody specific for CD28: Fv-mediated co-stimulation of T cells
AbstractThe most predominant co-stimulation pathway, which is critical for T cell activation and proliferation, is the CD28-B7 pathway. The anti-CD28 monoclonal antibody (mAb) also provides a co-stimulatory signal to T cells. In order to construct a functional Fv fragment (complex of VH and VL domains) of anti-CD28 antibody using a bacterial expression system, cDNA encoding the variable regions of immunoglobulin from 15E8 hybridoma cells was cloned and expressed in Escherichia coli. The Fv fragment was obtained as a soluble protein from the periplasmic fraction and showed a binding pattern similar to parental IgG. The Fv fragment induced proliferation of peripheral blood mononuclear cells in the presence of anti-CD3 or anti-CD2 mAb and enhanced anti-tumor activity of anti-MUC1×anti-CD3 bispecific antibody when tested with lymphokine-activated killer cells with T cell phenotype. Thus, the anti-CD28 Fv fragment will be promising not only for the study of co-stimulation, but also for cancer immunotherapy
- …