Propagation experiment of COMETS Ka/Q-band communication link for future satellite cellular system

Mobile/Personal Satellite Communication Systems in L/S-bands are going into the operational phase. In the future, they will be operated in much higher frequency bands, for example in Ka-band, because the available bandwidth in L-band is limited. Systems with large on-board antennas in higher frequencies allow the same configuration as terrestrial cellular radio systems, since the on-board antennas will have many small spot beams. This may be true especially in a low earth orbit system such as Teledesic, which will use Ka-band. The most important parameter of Satellite Cellular may be cell size, that is, a diameter of the spot beam. A system designer needs the local correlation data in a cell and the size of the correlative area. On the other hand, the most significant difficulty of Ka and higher band systems is the countermeasure to rain attenuation. Many-cell systems can manage the limited power of on-board transponders by controlling output power of each beam depending on the rain attenuation of each cell. If the cell size is equal to the correlative area, the system can probably achieve the maximum performance. Propagation data of Ka and higher band obtained in the past shows a long term cumulative feature and link availability, but do not indicate the correlative area. The Japanese COMETS satellite, which will be launched in February 1997, has transponders in Ka and Q-band. The CRL is planning to measure the correlative area using 21 GHz and 44 GHz CW transmissions from the COMETS

The Australian experiment with ETS-V

Land-mobile satellite propagation measurements were implemented at L Band (1.5 GHz) in South-Eastern Australia during an 11 day period in October 1988. Transmissions (CW) from both the Japanese ETS-5 and INMARSAT Pacific geostationary satellites were accessed. Previous measurements in this series were performed at both L Band (1.5 GHz) and UHF (870 MHz) in Central Maryland, North-Central Colorado, and the southern United States. The objectives of the Australian campaign were to expand the data base acquired in the U.S. to another continent, to validate a U.S. derived empirical model for estimating the fade distribution, to establish the effects of directive antennas, to assess the isolation between co- and cross-polarized transmissions, to derive estimates of fade as well as non-fade durations, and to evaluate diversity reception. All these objectives were met

Comparative analysis of seed and seedling irradiation with gamma rays and carbon ions for mutation induction in Arabidopsis

The molecular nature of mutations induced by ionizing radiation and chemical mutagens in plants is becoming clearer owing to the availability of high-throughput DNA sequencing technology. However, few studies have compared the induced mutations between different radiation qualities and between different irradiated materials with the same analysis method. To compare mutation induction between dry-seeds and seedlings irradiated with carbon ions and gamma rays in Arabidopsis, in this study we detected the mutations induced by seedling irradiation with gamma rays and analyzed the data together with data previously obtained for the other irradiation treatments. Mutation frequency at the equivalent dose for survival reduction was higher with gamma rays than with carbon ions, and was higher with dry-seed irradiation than with seedling irradiation. Carbon ions induced a higher frequency of deletions (2−99 bp) than gamma rays in the case of dry-seed irradiation, but this difference was less evident in the case of seedling irradiation. This result supported the inference that dry-seed irradiation under a lower water content more clearly reflects the difference in radiation quality. However, the ratio of rearrangements (inversions, translocations, and deletions larger than 100 bp), which are considered to be derived from the rejoining of two distantly located DNA breaks, was significantly higher with carbon ions than gamma rays irrespective of the irradiated material. This finding suggested that high-linear energy transfer radiation induced closely located DNA damage, irrespective of the water content of the material, that could lead to the generation of rearrangements. Taken together, the results provide an overall picture of radiation-induced mutation in Arabidopsis and will be useful for selection of a suitable radiation treatment for mutagenesis

Efficacy of fragmin/protamine microparticles containing fibroblast growth factor-2 (F/P MPs/FGF-2) to induce collateral vessels in a rabbit model of hindlimb ischemia

ObjectivesThe localized delivery of exogenous, angiogenic growth factors such as fibroblast growth factor (FGF)-2 has become a promising alternative treatment of peripheral artery disease (PAD) and critical limb ischemia (CLI). The present study describes the efficacy of fragmin/protamine microparticles containing FGF-2 (F/P-MPs/FGF-2) to promote vessel growth in a rabbit model of hindlimb ischemia.MethodsA total of 24 rabbits were used to construct a model of hindlimb ischemia by resection of the left femoral artery. The rabbits were randomly divided into four groups 10 days after surgery (day 0); group A: control (non-treated; 1 mL of phosphate-buffered saline [PBS]); group B: FGF-2 (100 μg FGF-2 in 1 mL PBS)-treated; group C: F/P-MPs (12 mg dried F/P MPs in 1 mL PBS)-treated; and group D; F/P MPs/FGF-2 (100 μg FGF-2 and 12 mg dried F/P MPs in 1 mL PBS)-treated (n = 6 each). The drugs were administered intramuscularly to each group. Blood flow and blood pressure were measured in each group on days 0, 14, and 28. Angiography was performed to assess arteriogenesis on day 28. The number of capillaries on day 28 was determined by direct counting CD31− and α-smooth muscle antibody (α-SMA)-positive vessels.ResultsNeither death nor wound infection was observed throughout the experiment. The F/P MPs/FGF-2-treated group showed marked improvement in the blood flow ratio, blood pressure ratio, and capillary number in comparison to the control group, FGF-2-treated group, and F/P MPs-treated group. The F/P MPs-treated group showed intermediate improvement in blood flow ratio and capillary number in comparison to the control group and FGF-2-treated group.ConclusionsThe F/P MPs/FGF-2-treated group strongly induced functional collateral vessels in the rabbit model of hindlimb ischemia, indicating a possible therapy for PAD.Clinical RelevancePAD due to atherosclerotic vascular disease is a major health problem. Despite recent advances in surgical and radiologic vascular techniques, certain patients with CLI are not suitable for revascularization. A variety of strategies have been tried to promote development of collateral vessels. F/P MPs can act as carriers for controlled release of FGF-2. The purpose of this study was to evaluate the efficacy of F/P MPs/FGF-2 to induce functional collateral vessels in a rabbit model of hindlimb ischemia. This study will lead to F/P MPs/FGF-2-therapy which is an effective therapeutic strategy for treating PAD patients in clinic

Sheet Dependence on Superconducting Gap in Oxygen-Deficient Iron-based Oxypnictide Superconductors NdFeAs0.85

Photoemission spectroscopy with low-energy tunable photons on oxygen-deficient iron-based oxypnictide superconductors NdFeAsO0.85 (Tc=52K) reveals a distinct photon-energy dependence of the electronic structure near the Fermi level (EF). A clear shift of the leading-edge can be observed in the superconducting states with 9.5 eV photons, while a clear Fermi cutoff with little leading-edge shift can be observed with 6.0 eV photons. The results are indicative of the superconducting gap opening not on the hole-like ones around Gamma (0,0) point but on the electron-like sheets around M(pi,pi) point.Comment: 8 pages, 3 figure

High-Energy Anomaly in the Band Dispersion of the Ruthenate Superconductor

We reveal a “high-energy anomaly" (HEA) in the band dispersion of the unconventional ruthenate superconductor Sr2RuO4, by means of high-resolution angle-resolved photoemission spectroscopy (ARPES) with tunable energy and polarization of incident photons. This observation provides another class of correlated materials exhibiting this anomaly beyond high-Tc cuprates. We demonstrate that two distinct types of band renormalization associated with and without the HEA occur as a natural consequence of the energetics in the bandwidth and the energy scale of the HEA. Our results are well reproduced by a simple analytical form of the self-energy based on the Fermi-liquid theory, indicating that the HEA exists at a characteristic energy scale of the multielectron excitations. We propose that the HEA universally emerges if the systems have such a characteristic energy scale inside of the bandwidth

ホウレンソウ雌性間性株における突然変異誘発ならびに低シュウ酸個体の選抜

This study was conducted to evalute mutagenesis in gynomonoecious spinach (Spinacia oleracea L.) plants for inducing low oxalate variants.Gamma-ray and ion beams of 220 MeV12C5+ and 50MeV 4He2+ ware used as mutagen in seed irradiation. Optimum dosages for irradiation were determined to be about 100Gy, 15-20Gy and 150-200Gy in gamma-ray, 12C5+ and 4He2+, respectively. In M2 generation, there was one line segregating albino seedlings, one line segregating xantha seedlings and two lines segregating dioesious spinach. To save on labor and time for analysis, selection of low oxalate variants in M2generation was conducted by a two-step selebtion which consisted of the first snalysis of bulked leaves from 2 plants as one specimen followed by the second analysis of selected individual plants. In the first analysis of 813 specimens, we selected 13 specimens as low and 9 specimens as high in oxalate content. In the second analysus, there was consistency in the distribution of low and high oxalate content corresponding to the first screening, indicating that selebtion of low oxalate variants could be achived by this two-step selebtion with half the labor and time for analysis as compares to non-bulked method. There were no clear differences in distribution of oxalate content between M3progenies of plants selected as low or high oxalate content, suggesting that the low oxalate content in plants isolated in M2generation was not of a genetic origin. From these results, it seems to be necessary to explore a variant with obvious deviation from the bontinuous variation of oxalate content in the M 2 generation.本実験では，ホウレンソウ雌性間性株における突然変異誘発ならびに低シュウ酸個体の選抜を試みた．種子照射の変異原としては，γ線と220MeV 12

Wireless data transmission in a 560-GHz band using low-phase-noise terahertz wave generated by photomixing of a pair of distributed feedback lasers injection-locking to Kerr micro-resonator soliton comb

The demand for higher data rates in next-generation mobile wireless communication systems (6G) has led to significant interest in terahertz (THz) waves as a high-frequency, broad modulation bandwidth carrier wave. In this study, we propose and demonstrate a wireless data transfer in the 560-GHz band using low-phase-noise THz waves generated by photomixing of a pair of distributed feedback lasers injection-locking to Kerr micro-resonator soliton comb. Experimental results showed near-error-free on-off keying (OOK) data transfer at 1 Gbit/s in the 560-GHz band, with a Q-factor of 6.23, surpassing the error-free limit. Also, modulation formats of binary phase shift keying (BPSK) and quadrature phase shift keying (QPSK) were successfully used, showing clear constellation diagrams and relatively low root mean squared error vector magnitude (rms EVM) values of 23.9% and 23.6%, respectively. Moreover, data transfer at 0.4 Gbit/s in 16 quadrature amplitude modulation (16QAM) demonstrated clear isolated symbols and achieved a low rms EVM value of 8.1%, complying with the IEEE 802.15.3d standard amendment. These demonstrations highlight the potential of using injection-locked DFB lasers with the Kerr micro-resonator soliton comb to achieve high-quality, high-speed wireless data transfer in the 560-GHz band. These findings contribute significantly to the advancement of wireless communication technology in the THz frequency range and pave the way for the realization of 6G wireless communication systems

Medium-chain fatty acids suppress lipotoxicity-induced hepatic fibrosis via the immunomodulating receptor GPR84

食事性肥満から肝炎発症に関わる制御因子の同定 --中鎖脂肪酸油による予防・GPR84標的NASH治療薬の可能性--. 京都大学プレスリリース. 2023-01-18.Medium-chain triglycerides (MCTs), which consist of medium-chain fatty acids (MCFAs), are unique forms of dietary fat with various health benefits. G protein–coupled 84 (GPR84) acts as a receptor for MCFAs (especially C10:0 and C12:0); however, GPR84 is still considered an orphan receptor, and the nutritional signaling of endogenous and dietary MCFAs via GPR84 remains unclear. Here, we showed that endogenous MCFA-mediated GPR84 signaling protected hepatic functions from diet-induced lipotoxicity. Under high-fat diet (HFD) conditions, GPR84-deficient mice exhibited nonalcoholic steatohepatitis (NASH) and the progression of hepatic fibrosis but not steatosis. With markedly increased hepatic MCFA levels under HFD, GPR84 suppressed lipotoxicity-induced macrophage overactivation. Thus, GPR84 is an immunomodulating receptor that suppresses excessive dietary fat intake–induced toxicity by sensing increases in MCFAs. Additionally, administering MCTs, MCFAs (C10:0 or C12:0, but not C8:0), or GPR84 agonists effectively improved NASH in mouse models. Therefore, exogenous GPR84 stimulation is a potential strategy for treating NASH