Advanced mobile satellite communications using COMETS satellite in MM-wave and Ka-band

Early in the 21st century, the demand for personal communications using mobile, hand-held, and VSAT terminals will rapidly increase. In a future system, many different types of services should be provided with one-hop connection. The Communications Research Laboratory (CRL) has studied a future advanced mobile satellite communications system using millimeter wave and Ka band. In 1990, CRL started the Communications and Broadcasting Engineering Test Satellite (COMETS) project. The satellite has been developed in conjunction with NASDA and will be launched in 1997. This paper describes the COMETS payload configuration and the experimental system for the advanced mobile communications mission

Microglia in Alzheimer's Disease: Risk Factors and Inflammation

Microglia are resident immune cells in the central nervous system (CNS) that originate from myeloid progenitor cells in the embryonic yolk sac and are maintained independently of circulating monocytes throughout life. In the healthy state, microglia are highly dynamic and control the environment by rapidly extending and retracting their processes. When the CNS is inflamed, microglia can give rise to macrophages, but the regulatory mechanisms underlying this process have not been fully elucidated. Recent genetic studies have suggested that microglial function is compromised in Alzheimer's disease (AD), and that environmental factors such as diet and brain injury also affect microglial activation. In addition, studies of triggering receptor expressed on myeloid cells 2-deficiency in AD mice revealed heterogeneous microglial reactions at different disease stages, complicating the therapeutic strategy for AD. In this paper, we describe the relationship between genetic and environmental risk factors and the roles of microglia in AD pathogenesis, based on studies performed in human patients and animal models. We also discuss the mechanisms of inflammasomes and neurotransmitters in microglia, which accelerate the development of amyloid-β and tau pathology

The neuroprotective effects of milk fat globule-EGF factor 8 against oligomeric amyloid β toxicity

BACKGROUND: Phosphatidylserine receptor is a key molecule that mediates the phagocytosis of apoptotic cells. Milk fat globule-EGF factor 8 (MFG-E8) is a phosphatidylserine receptor that is expressed on various macrophage lineage cells, including microglia in the central nervous system (CNS). Targeted clearance of degenerated neurons by microglia is essential to maintain healthy neural networks. We previously showed that the CX3C chemokine fractalkine is secreted from degenerated neurons and accelerates microglial clearance of neuronal debris via inducing the release of MFG-E8. However, the mechanisms by which microglia produce MFG-E8 and the precise functions of MFG-E8 are unknown. METHODS: The release of MFG-E8 from microglia treated with conditioned medium from neurons exposed to neurotoxic substances, glutamate or oligomeric amyloid β (oAβ) was measured by ELISA. The neuroprotective effects of MFG-E8 and MFG-E8 − induced microglial phagocytosis of oAβ were assessed by immunocytochemistry. The effects of MFG-E8 on the production of the anti-oxidative enzyme hemeoxygenase-1 (HO-1) were determined by ELISA and immunocytochemisty. RESULTS: MFG-E8 was induced in microglia treated with conditioned medium from neurons that had been exposed to neurotoxicants, glutamate or oAβ. MFG-E8 significantly attenuated oAβ-induced neuronal cell death in a primary neuron − microglia coculture system. Microglial phagocytosis of oAβ was accelerated by MFG-E8 treatment due to increased CD47 expression in the absence of neurotoxic molecule production, such as tumor necrosis factor-α, nitric oxide, and glutamate. MFG-E8 − treated microglia induced nuclear factor E(2) − related factor 2 (Nrf2) − mediated HO-1 production, which also contributed to neuroprotection. CONCLUSIONS: These results suggest that microglia release MFG-E8 in response to signals from degenerated neurons and that MFG-E8 protects oAβ-induced neuronal cell death by promoting microglial phagocytic activity and activating the Nrf2-HO-1 pathway. Thus, MFG-E8 may have novel roles as a neuroprotectant in neurodegenerative conditions

Thermal Control System to Easily Cool the GAPS Balloon-borne Instrument on the Ground

This study developed a novel thermal control system to cool detectors of the General AntiParticle Spectrometer (GAPS) before its flights. GAPS is a balloon-borne cosmic-ray observation experiment. In its payload, GAPS contains over 1000 silicon detectors that must be cooled below -40^{\circ}\mbox{C}. All detectors are thermally coupled to a unique heat-pipe system (HPS) that transfers heat from the detectors to a radiator. The radiator is designed to be cooled below -50^{\circ}\mbox{C} during the flight by exposure to space. The pre-flight state of the detectors is checked on the ground at 1 atm and ambient room temperature, but the radiator cannot be similarly cooled. The authors have developed a ground cooling system (GCS) to chill the detectors for ground testing. The GCS consists of a cold plate, a chiller, and insulating foam. The cold plate is designed to be attached to the radiator and cooled by a coolant pumped by the chiller. The payload configuration, including the HPS, can be the same as that of the flight. The GCS design was validated by thermal tests using a scale model. The GCS design is simple and provides a practical guideline, including a simple estimation of appropriate thermal insulation thickness, which can be easily adapted to other applications.Comment: 8 pages, 14 figures, 3 table

Lewis Acid and Fluoroalcohol Mediated Nucleophilic Addition to the C2 Position of Indoles

Indole readily undergoes nucleophilic substitution at the C3 site, and many indole derivatives have been functionalized using this property. Indole also forms indolium, which allows electrophilic addition in acidic conditions, but current examples have been limited to intramolecular reactions. C2 site-selective nucleophilic addition to indole derivatives using fluoroalcohol and a Lewis acid was developed

Fabrication of Planar Power Inductor for Embedded Passives in LSI Package for Hundreds Megahertz Switching DC-DC Buck Converter

Recently, research and development of integrated low-voltage dc-dc converter to LSIs has been active. In order to realize such integrated dc power supply, power magnetic devices must be integrated in it. The authors have fabricated planar power inductor embedded in LSI package for hundreds megahertz switching dc-dc buck converter. In this study, two types of planar power inductors have been fabricated: one was spin-sprayed Zn-ferrite thick film magnetic core inductor, and the other was composite magnetic core (Fe-based amorphous/polyimide) inductor. Footprint of the fabricated inductors was 850 x 850 mu m(2), their inductance was about 10 nH, and the quality factor Q was about 20 at 100 MHz. The rating current which depends on the superimposed dc characteristic was at least up to 2 A.ArticleIEEE TRANSACTIONS ON MAGNETICS. 47(10):3204-3207 (2011)journal articl

Multifrequency VLBI Observations of the Broad Absorption Line Quasar J1020+4320: Recently Restarted Jet Activity?

This paper reports very-long-baseline interferometry observations of the radio-loud broad absorption line (BAL) quasar J1020+4320 at 1.7, 2.3, 6.7, and 8.4 GHz using the Japanese VLBI network (JVN) and European VLBI network (EVN). The radio morphology is compact with a size of ~10 pc. The convex radio spectrum is stable over the last decade; an observed peak frequency of 3.2 GHz is equivalent to 9.5 GHz in the rest frame, suggesting an age of the order of ~100 years as a radio source, according to an observed correlation between linear size and peak frequency of compact steep spectrum (CSS) and giga-hertz peaked spectrum (GPS) radio sources. A low-frequency radio excess suggests relic of past jet activity. J1020+4320 may be one of the quasars with recurrent and short-lived jet activity during a BAL-outflowing phase.Comment: 7 pages, 2 figures, 2 tables, accepted for publication in PAS

Isolation and identification of the antimicrobial substance included in tempeh using Rhizopus stolonifer NBRC 30816 for fermentation

In this study, we focus on the antimicrobial properties of tempeh, a soybean fermented food, against oral bacteria. Tempeh showed antimicrobial activity against dental caries pathogenic bacterium Streptococcus mutans at a final concentration of 1 mg/mL. An antimicrobial substance contained in tempeh was present in the 100 kDa or greater fraction generated by ultrafiltration, but it was found not to be proteinaceous by native-PAGE, SDS-PAGE and protein degradation tests. Next, when the fraction was purified with an ODS column, the 80% and 100% methanol eluates showed antimicrobial activity against S. mutans. The 100% methanol eluate was further subjected to a 2nd column purification, and isolation of the target was confirmed by HPLC. When the isolated material was analyzed by ESI-MS, the m/z was 279.234. Further analysis by Raman spectroscopy revealed a peak similar to linoleic acid. This substance also possessed antimicrobial properties equivalent to linoleic acid

On the Possibility of Observing the Double Emission Line Feature of H2_2 and HD from Primordial Molecular Cloud Cores

We study the prospects for observing H$_2$ and HD emission during the assembly of primordial molecular cloud cores. The primordial molecular cloud cores, which resemble those at the present epoch, can emerge around $1+z \sim 20$ according to recent numerical simulations. A core typically contracts to form the first generation of stars and the contracting core emits H$_2$ and HD line radiation. These lines show a double peak feature. The higher peak is the H$_2$ line of the $J=2-0$ (v=0) rotational transition, and the lower peak is the HD line of the $J=4-3$ (v=0) rotational transition. The ratio of the peaks is about 20, this value characterising the emission from primordial galaxies. The expected emission flux at the redshift of $1+z \sim 20$ (e.g. $\Omega_m = 0.3$ and $\Omega_\Lambda =0.7$), in the $J=2-0$ (v=0) line of H$_2$ occurs at a rate $\sim 2 \times 10^{-7}$ Jy, and in the $J=4-3$ (v=0) line of HD at a rate $\sim 4 \times 10^{-9}$ Jy. The former has a frequency of 5.33179$\times 10^{11}$ Hz and the latter is at 5.33388 $\times 10^{11}$Hz, respectively. Since the frequency resolution of ALMA is about 40 kHz, the double peak is resolvable. While an individual object is not observable even by ALMA, the expected assembly of primordial star clusters on subgalactic scales can result in fluxes at the 2000-50 $\mu$Jy level. These are marginally observable. The first peak of H$_2$ is produced when the core gas cools due to HD cooling, while the second peak of HD occurs because the medium maintains thermal balance by H$_2$ cooling which must be enhanced by three-body reactions to form H$_2$ itself.Comment: 24 pages, 5 figures. MNRAS (Accepted