Receiver-Triggered Handshake Protocol for DTN in Disaster Area

When a disaster hits a wide area, communication services for public use will be rendered unavailable. This will make it difficult to confirm the safety of people in the disaster area. A solution to this problem is to form delay/disruption tolerant networks (DTN) using mobile terminals of victims, those of rescuers, who serve as information carriers, and terminals (servers) in shelters. In this paper, we propose using a receiver-triggered handshake protocol for communication between these terminals. We have developed the bundle layer protocol for this handshake method. The proposed method has been implemented on a network simulator to build an evaluation environment. The disaster area has been modeled on an area around Shinjuku Station in Tokyo. Victims are randomly distributed in the area. We have compared the proposed method with Epidemic Routing and Spray and Wait in terms of the delivery rate at which messages reach their destinations, and the length of time taken for messages to reach their destinations. We have found that the delivery rate of the three methods are, more or less, the same, but that the proposed method is superior to the other two methods in terms of storage usage and battery consumption of terminals, and the number of bundles generated in the network

Transgenic zebrafish reveals novel mechanisms of translational control of cyclin B1 mRNA in oocytes

Temporal translation control of localized mRNA is crucial for regulating various cellular and developmental processes. However, little is known about the mechanisms of temporal translation control of localized mRNA due to the limitation in technology. cyclin B1 mRNA at the animal polar cytoplasm of immature zebrafish oocytes is translationally repressed, and its activation is temporally regulated during maturation. Mechanisms of cyclin B1 translation in oocytes were analyzed using transgenic zebrafish in which reporter mRNAs are produced from transgenes introduced into the genome through transcription in the nucleus followed by transport to the cytoplasm, as in endogenous mRNAs. Real-time imaging of the site and timing of translation showed that mRNAs containing the full-length cyclin B1 sequence precisely mimic the localization and translation of endogenous cyclin B1 mRNA. However, mRNAs containing cyclin B1 3' untranslated region but lacking open reading frame (ORF) underwent abnormal localization and precocious translational activation, indicating the significance of the ORF in translational control of cyclin B1 mRNA. Our genetic approach in combination with real-time imaging of the translation site and timing provides a novel insight into the mechanisms of temporal control of translation

Possible Involvement of Phosphatidylinositol 3-Kinase, but Not Protein Kinase B or Glycogen Synthase Kinase 3β, in Progesterone-Induced Oocyte Maturation in the Japanese Brown Frog, Rana japonica

It is known that amphibian oocytes undergo maturation through the formation and activation of maturation-promoting factor (MPF) in response to stimulation by the maturation-inducing hormone progesterone; however, the signal transduction pathway that links the hormonal stimulation on the oocyte surface to the activation of MPF in the oocyte cytoplasm remains a mystery. The aim of this study was to investigate whether the signal transduction mediated by phosphatidylinositol 3-kinase (PI3K), protein kinase B (PKB), and glycogen synthase kinase 3β (GSK3β) is involved in progesterone-induced oocyte maturation in the Japanese brown frog, Rana japonica. Inhibitors of PI3K, wortmannin and LY294002, inhibited progesterone-stimulated germinal vesicle breakdown (GVBD) only when the oocytes were treated at the initial phase of maturation, suggesting that PI3K is involved in the progesterone-induced maturation of Rana oocytes. However, we also obtained results suggesting that PKB and GSK3β are not involved in Rana oocyte maturation. A constitutively active PKB expressed in the oocytes failed to induce GVBD in the absence of progesterone despite its high level of kinase activity. A Myc-tagged PKB expressed in the oocytes (used to monitor endogenous PKB activity) was not activated in the process of progesterone-induced oocyte maturation. Overexpression of GSK3β, which is reported to retard the progress of Xenopus oocyte maturation, had no effect on Rana oocyte maturation. On the basis of these results, we propose that PI3K is involved in the initiation of Rana oocyte maturation, but that neither PKB nor GSK3βis a component of the PI3K signal transduction pathway

Noninvasive and Safe Cell Viability Assay for Breast Cancer MCF-7 Cells Using Natural Food Pigment

A dye exclusion test (DET) was performed to determine the viability of human breast cancer cells MCF-7, using natural food pigments as compared with trypan blue (TB), a typical synthetic dye for DET known to exhibit teratogenicity and cytotoxicity. We demonstrated that Monascus pigment (MP) is noninvasive to living cells and can effectively stain only dead cells. This study is the first verification of the applicability of MP to cancer cells. The appropriate MP concentration was 0.4% (0.02% as the concentration of pure MP) and all the dead cells were stained within 10 min. We found that the cell proliferation or the reduced nicotinamide adenine dinucleotide (NADH) activity of living cells was maintained over 48 h. Although 0.1% TB did not show an increase in dead cells, a marked decrease in NADH activity was confirmed. In addition, even when MP coexisted with cisplatin, staining of dead cells was maintained for 47 h, indicating stability to drugs (reagents). The cost of MP is estimated to be about 1/10 of TB. The fact that MP can be used as a cell viability determination reagent for Euglena and Paramecium, as shown in preceding papers, and also for MCF-7, as shown in this paper, indicates the possibility of application in more cells of different species

Magnetic properties of Fe-Ni-system films prepared by electroless deposition

We prepared Fe-Ni thick-films (> 1 μm) using an electroless deposition method and evaluated the magnetic properties and the crystal structures. The deposition rate depended on the concentration of dimethylamine-borane (DMAB), which is a reducing agent used in the present study, and we obtained a high deposition rate (> 10 μm/h) for Fe30Ni70 films when the DMAB concentration is higher than 3 g/L. From structural analyses of the films, we found that the films have very fine fcc Fe-Ni crystals in the amorphous magnetic phase. From the investigation of Co additives for the improvement in the surface conditions, we confirmed that a small amount of Co effectively works to obtain the smooth surfaces. As a result, we could obtain the Fe-Ni-system thick-films with low coercivity (50 A/m) and smooth surfaces