Analysis of genetic mutations is one of the most effective ways to investigate gene function. We now have methods that allow for mass production of mutant lines and cells in a variety of model ...species. Recently, large numbers of mutant lines have been generated by both 'loss-of-function' and 'gain-of-function' techniques. In parallel, phenotypic information covering various mutant resources has been acquired and released in web-based databases. As a result, significant progress in comprehensive phenotype analysis is being made through the use of these tools. Arabidopsis and rice are two major model plant species in which genome sequencing projects have been completed. Arabidopsis is the most widely used experimental plant, with a large number of mutant resources and several examples of systematic phenotype analysis. Rice is a major crop species and is used as a model plant, with an increasing number of mutant resources. Other plant species are also being employed in functional genetics research. In this review, the present status of mutant resources for large-scale studies of gene function in plant research and the current perspective on using loss-of-function and gain-of-function mutants in phenome research will be discussed.
Abstract
One of the most important problems in neutrino physics is whether neutrinos are Majorana particles or Dirac ones. If a neutrino has a Majorana nature, neutrinoless double beta decay (
...$0\nu2\beta$
) certainly takes place. On the other hand, there is a theory in which neutrinoless quadruple beta decay (
$0\nu4\beta$
) is possible, allowing for lepton number violation by four units, even if a neutrino has a Dirac nature. Since the half-lives of both
$0\nu2\beta$
and
$0\nu4\beta$
are theoretically expected to be very long, detectors have to have an excellent capability to eliminate backgrounds. We have been developing a series of electron momentum analyzers called the drift chamber beta-ray analyzer (DCBA) at KEK for double beta decay experiments. DCBA consists of drift chambers detecting charged particle tracks, and a superconducting solenoid serving a uniform magnetic field. Since the momentum acceptance is in the region of 0.5–3.5 MeV/
$c$
, it is easy to eliminate background particles like alpha particles, protons, and muons, which have much higher momenta because of their large masses. The particle identification property and the 3D position determination capability are powerful tools to search for
$0\nu2\beta$
and
$0\nu4\beta$
events. In this article, we describe the performance of DCBA as well as the details of the detector construction processes.
A remote monitoring system was developed based on the software infrastructure of the Experimental Physics and Industrial Control System (EPICS) for the cryogenic system of superconducting magnets in ...the interaction region of the SuperKEKB accelerator. The SuperKEKB has been constructed to conduct high-energy physics experiments at KEK. These superconducting magnets consist of three apparatuses, the Belle II detector solenoid, and QCSL and QCSR accelerator magnets. They are each contained in three cryostats cooled by dedicated helium cryogenic systems. The monitoring system was developed to read data of the EX-8000, which is an integrated instrumentation system to control all cryogenic components. The monitoring system uses the I/O control tools of EPICS software for TCP/IP, archiving techniques using a relational database, and easy human-computer interface. Using this monitoring system, it is possible to remotely monitor all real-time data of the superconducting magnets and cryogenic systems. It is also convenient to share data among multiple groups.
The aim of the DCBA (Drift Chamber Beta-ray Analyzer) experiment is to search for neutrinoless double beta decay (
0
ν
β
β
). The half-life of
0
ν
β
β
is expected to give us the information of ...Majorana nature and the absolute mass scale of neutrinos. A prototype test apparatus DCBA-T2 has the energy resolution of about 150
keV (FWHM) around 1
MeV. In order to check the detector performance, engineering runs detecting double beta decay of
100Mo started in May 2009 using natural Mo, which contains 9.6% of
100Mo. Ten candidates of the double beta decay
(
β
β
)
have been detected so far. It has been found that the background events due to
214Bi decay are distinguishable from the double beta decays by detecting
α
-particles
from
214Po.
The experiment of neutrinoless double beta decay
is the only realistic method for investigating the Majorana nature and the absolute mass scale of neutrinos. An R
D project called Drift Chamber ...Beta-ray Analyzer (DCBA) has been developing a magnetic tracking detector for
experiments at KEK. A superconducting solenoid magnet (SCSM) has been constructed to produce a uniform magnetic field for the prototype test facility called DCBA-T3. The results of SCSM test runs are described, as well as its design studies. Since the SCSM is a prototype magnet for a future detector temporarily called Magnetic Tracking Detector (MTD), it is essential to understand its long-term operation. The experience of about two years of operation is also described.
It is well-known that the wind speed affecting the pantograph is stronger in tunnels than in the open air on the Shinkansen line. Therefore, the authors measured wind speed, wind direction, dynamic ...behavior of the overhead contacts line and metal fittings when the Shinkansen train ran through a tunnel at high-speed. This paper discusses the influence of the air flow in a tunnel caused by a high-speed train on current collection performance and the overhead contacts lines. Further, the aerodynamic upward force of the pantograph was estimated on the basis of the measured results. Finally, using the motion simulation of a pantograph and overhead contacts line, their dynamic characteristics at high-speed were evaluated.
SuperKEKB beam final focus superconducting magnet system Ohuchi, N.; Arimoto, Y.; Akai, K. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
01/2022, Volume:
1021
Journal Article
Peer reviewed
Open access
The SuperKEKB was designed and constructed as the upgraded accelerator of KEKB. In this accelerator design, the nano-beam scheme of collision was applied and a luminosity of 8 × 1035 cm−2s−1 was ...targeted. In the design, the beam final focus system was the key component in the accelerator hardware elements. This final focus system consists of 55 superconducting magnets. In this paper, the designs of the magnets, the cryostats and the cryogenic system are shown, and the field measurement results are reported. The SuperKEKB beam operation with the final focus system started on 2018 March 19, and the magnet quench events up to 2020 December 16 are described.
By using the method of grey relative analysis, which can account for the time sequence, this paper carries out analyses for the relative relationship among the four major factors affecting the rural ...household biofuels consumption of each province/region in China through period 1991–1999. Based on the analytical results of the relative degrees and relative polarities, forecast models on the future consumption of crop residues and firewood in Chinese rural households are proposed. Furthermore, the future consumption of rural crop residues and firewood up to the year of 2020 is forecasted. These four factors include population per rural household, income per rural household, educational situation of laborers per rural household and food area per rural household. Results show that these four factors are closely related to rural household biofuels consumption in China. Among these, the relative relationship of population and food area per rural household to rural household biofuels consumption is positive, and that of the income and educational situation of laborers per household is negative. Forecast results show that the precision accuracies of forecast models are higher. The future total rural household biofuels consumption will decrease to 3388 PJ in 2020 from 6032 PJ in 1999 in China. The average annual decline rate in this period will reach 2.8%. This indicates that the rural household energy consumption will enter into a new stage in which biofuels will be gradually replaced by the high-quality energy types (with high combustion efficiency and easy to use), such as coal, gas, LPG and electricity, along with improvements in living standards and educational level in the rural household.
Gain-of-function approaches have been used as an alternative or complementary method to loss-of-function approaches as well as to confer new functions to plants. Gain-of-function is achieved by ...increasing gene expression levels through the random activation of endogenous genes by transcriptional enhancers or the expression of individual transgenes by transformation. The advantages of gain-of-function approaches compared to loss-of-function approaches for the characterization of gene functions include the abilities to (a) analyze individual gene family members, (b) characterize the function of genes from nonmodel plants using a heterologous expression system, and (c) identify genes that confer stress tolerance to plants that result from the introduction of transgenes. In this review, we describe the current status of gain-of-function mutagenesis and provide several examples of how gene functions have been characterized via high-throughput screening using gain-of-function technology.
In order to search for neutrinoless double beta-decay, the DCBA (Drift Chamber Beta-ray Analyzer) experiment uses a momentum analyzer, which mainly consists of drift chamber and a uniform magnetic ...field. A beta ray from a source plate make helical trajectory in the drift chamber owing to the magnetic field. Momentum of each beta ray is obtained by three-dimensional track reconstruction. A test prototype called DCBA-T2 has been constructed and operated at KEK. Another prototype DCBA-T3 is also under construction to improve the energy resolution. The results of DCBA-T2 engineering run are described together with the status of DCBA-T3.
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