182 research outputs found
Neutrinoful Universe
The Standard Model of particle physics fails to explain the important pieces
in the standard cosmology, such as inflation, baryogenesis, and dark matter of
the Universe. We consider the possibility that the sector to generate small
neutrino masses is responsible for all of them; the inflation is driven by the
Higgs field to break gauge symmetry which provides the Majorana masses to
the right-handed neutrinos, and the reheating process by the decay of the
Higgs boson supplies the second lightest right-handed neutrinos whose CP
violating decays produce asymmetry, a la, leptogenesis. The lightest
right-handed neutrinos are also produced by the reheating process, and remain
today as the dark matter of the Universe. In the minimal model of the inflaton
potential, one can set the parameter of the potential by the data from CMB
observations including the BICEP2 and the Planck experiments. In such a
scenario, the mass of the dark matter particle is predicted to be of the order
of PeV. We find that the decay of the PeV right-handed neutrinos can explain
the high-energy neutrino flux observed at the IceCube experiments if the
lifetime is of the order of s.Comment: 21 pages, 9 figures; v2: added reference and fixed typ
GATA-6 DNA binding protein expressed in human gastric adenocarcinoma MKN45 cells
AbstractA cDNA for the GATA-6 (GATA-GT1) DNA binding protein was cloned from a library of the human gastric adenocarcinoma cell line MKN45. The deduced amino acid sequence (449 residues) indicates that the primary structure of human GATA-6 is highly homologous to that of the rat protein. The potential phosphorylation site for protein kinases (A and C), and histidine and alanine clusters are conserved. Whereas the rat H+/K+-ATPase α and β subunit genes have two and three GATA protein binding sites in their promoter regions, respectively, the human α subunit gene has only one binding site [Maeda, M., Kubo, K., Nishi, T. and Futai, M. (1996) J. Exp. Biol. 199, 513–520]. We cloned the 5′-upstream region of the human H+/K+-ATPase β subunit gene by genome walking and found that it also has a single GATA protein binding site near the TATA ☐. The GATA sites of the human α and β subunit genes are recognized by the zinc finger domain of human GATA-6. The conservation of the GATA protein binding sites suggests that they are important for the gene regulation of the human and rat H+/K+-ATPase
Western North Pacific Integrated Physical-Biogeochemical Ocean Observation Experiment (INBOX): Part 1.Specifications and chronology of the S1-INBOX floats
An interdisciplinary project called the Western North Pacific Integrated Physical-Biogeochemical Ocean Observation Experiment (INBOX) has been conducted since 2011. In the oligotrophic subtropics south of the Kuroshio Extension near biogeochemical mooring S1 (30° N, 145° E), 18 floats, each with a dissolved oxygen sensor, have been deployed in a 150 × 150 km square area. With the horizontal (30 km) and temporal (2 days) resolution of the data, we observed an upper ocean structure associated with mesoscale eddies and ocean responses to atmospheric forcing. The data set obtained from the S1-INBOX study was used to elucidate the impacts of physical processes on biogeochemical phenomena. This article is the first in a series of articles: specific information about the floats and a chronology of events are provided
Crystal Structure and Activity of the Endoribonuclease Domain of the piRNA Pathway Factor Maelstrom
SummaryPIWI-interacting RNAs (piRNAs) protect the genome from transposons in animal gonads. Maelstrom (Mael) is an evolutionarily conserved protein, composed of a high-mobility group (HMG) domain and a MAEL domain, and is essential for piRNA-mediated transcriptional transposon silencing in various species, such as Drosophila and mice. However, its structure and biochemical function have remained elusive. Here, we report the crystal structure of the MAEL domain from Drosophila melanogaster Mael, at 1.6 Å resolution. The structure reveals that the MAEL domain has an RNase H-like fold but lacks canonical catalytic residues conserved among RNase H-like superfamily nucleases. Our biochemical analyses reveal that the MAEL domain exhibits single-stranded RNA (ssRNA)-specific endonuclease activity. Our cell-based analyses further indicate that ssRNA cleavage activity appears dispensable for piRNA-mediated transcriptional transposon silencing in Drosophila. Our findings provide clues toward understanding the multiple roles of Mael in the piRNA pathway
Higgs-mediated muon-electron conversion process in supersymmetric seesaw model
We study the effect of the Higgs-exchange diagram for the lepton flavor
violating muon-electron conversion process in nuclei in the supersymmetric
seesaw model. The contribution is significant for a large value of tan beta and
a small value of a neutral heavy Higgs boson mass, in which case the ratio of
the branching ratios of B(mu N -> e N) / B(mu -> e gamma) is enhanced. We also
show that the target atom dependence of the conversion branching ratio provides
information on the size of the Higgs exchange diagram.Comment: 12 pages, 2 figures, a reference adde
Ad4BP/SF-1 regulates cholesterol synthesis to boost the production of steroids
Housekeeping metabolic pathways such as glycolysis are active in all cell types. In addition, many types of cells are equipped with cell-specific metabolic pathways. To properly perform their functions, housekeeping and cell-specific metabolic pathways must function cooperatively. However, the regulatory mechanisms that couple metabolic pathways remain largely unknown. Recently, we showed that the steroidogenic cell-specific nuclear receptor Ad4BP/ SF-1, which regulates steroidogenic genes, also regulates housekeeping glycolytic genes. Here, we identify cholesterogenic genes as the targets of Ad4BP/SF-1. Further, we reveal that Ad4BP/SF-1 regulates Hummr, a candidate mediator of cholesterol transport from endoplasmic reticula to mitochondria. Given that cholesterol is the starting material for steroidogenesis and is synthesized from acetyl-CoA, which partly originates from glucose, our results suggest that multiple biological processes involved in synthesizing steroid hormones are governed by Ad4BP/SF-1. To our knowledge, this study provides the first example where housekeeping and cell-specific metabolism are coordinated at the transcriptional level.This work was supported by Grants 16H05142 (K.M.), 17H06427 (K.M.), 16K08593 (T.B.), and 17J03270 (M.I.) from the Japan Society for the Promotion of Science (JSPS) KAKENHI; The Uehara Memorial Foundation (K.M.); Takeda Science Foundation (T.B.); The Shin-Nihon of Advanced Medical Research (T.B.).Supplementary information accompanies this paper at https://doi.org/10.1038/s42003-018-0020-z
Model error compensator design for continuous- and discrete-time non-minimum phase systems with polytopic-type uncertainties
This paper presents a design for a model error compensator with a parallel feedforward compensator for continuous- and discrete-time non-minimum phase multiple input multiple output (MIMO) plants. The model error compensator can easily achieve robustness for several types of control systems. By appending the compensator to the actual plant, the output trajectory of the plant can be made close to that of the control system with the intended nominal model. Our previous study proposed a design for the model error compensator using particle swarm optimization and linear matrix inequalities based on the common Lyapunov function. The compensator design for the plants addresses polytopic-type uncertainties. However, it is challenging to design the appropriate gain for the model error compensator if the plant is a non-minimum phase MIMO system. In this study, a parallel feedforward compensator is attached to the model error compensator to achieve minimum phase characteristics. An evaluation system, including a parallel feedforward compensator, can be derived as a system with polytopic uncertainties via the addition of some assumptions. Thus, it is easy to design the gain of the model error compensator in the proposed method and achieve robust performance. The effectiveness of the proposed design is evaluated using numerical examples
- …