Colocalization of MCM8 and MCM7 with proteins involved in distinct aspects of DNA replication

Minichromosome maintenance (MCM) proteins are essential for DNA replication in eukaryotes. A subcomplex of the MCM2-7 family members, initially characterized in yeast, is thought to serve as a eukaryotic DNA replicative helicase. MCM8 is a new family member, not present in yeast, which may function alone or with other family members in aspects of DNA metabolism, including replication initiation and elongation. Through the use of chromatin immunoprecipitation, we find that MCM8, like MCM7, colocalizes on a specific DNA segment of the c-MYC replication initiation zone (c-MYC replicator) with Cdc6, a protein potentially involved in loading MCM proteins onto DNA. The association between MCM8 and MCM7 peaks in mid G1, at the time of assembly of the prereplication complex. The association of both MCM proteins with Cdc6, however, continues even after DNA replication is complete. We also find that MCM8 colocalizes at the c-MYC replicator with chromatin-bound Cdk2. Our data indicate that any role MCM8 may play in elongation is likely to be discontinuous, in its association with DNA, from a potential role in initiation. Using immunogold electron microscopy we show that MCM8 and MCM7 differ in spatial relation to RPA70 during S phase. Our data strongly suggest that MCM8 functions with other known replication proteins in processes which accompany DNA replication, especially initiation, and which are specifically adapted to suit higher eukaryotes.     

High-pressure synthesis of novel compounds in an Mg–Ni system

High-pressure works are attractive techniques to obtain new compounds, such as alkali or alkaline earth metal-based systems. The atomic radius of Mg under GPa pressure is considerably smaller compared with transition metals; as such, it may be preferable to synthesize novel intermetallic compounds and hydrides by using high-pressure techniques. In this study, novel compounds were synthesized in an Mg–Ni system by a high-pressure technique using a cubic-anvil-type apparatus.A novel Mg₆Ni intermetallic compound was obtained by exposing a mixture of Mg and Ni to 6 GPa at 900 °C for 2 h. The crystal structure of the compound is a tetragonal F-43m structure with a lattice parameter of a=1.9987(1) nm. This compound decomposed to Mg and Mg₂Ni phases at 278 °C with exothermic reaction.As is well known, MgNi₂ does not form hydrides under conventional hydrogenation conditions, hence we investigated the reactivity of MgNi₂ with highly pressurized hydrogen. It was found that the MgNi₂ was able to form MgNi₂H_3.2 by treatment at 700 °C for 2 h under 5 GPa with a hydrogen source, leading to a hydrogen capacity of 2.23 mass%. This novel hydride was found to be a tetragonal MoSi₂-type structure (I4/mmm) with lattice parameters of a=0.327(3) nm and c=0.878(9) nm. The dehydrogenation of this hydride occurred at 187 °C with endothermic reaction, and caused decomposition into C36-type MgNi₂. This hydride had solubility of Ni content and its thermal stability decreased with increasing Ni content.     

Capacitance improvement of supercapacitor active material based on activated carbon fiber working with a Li-ion containing electrolyte

In an attempt to provide a favorable active material of Li⁺ supercapacitor for HEV use, we modified the surface of an activated carbon fiber felt by coating with some transition metal oxides after mild-oxidation treatment. Major source of enhancing capacitance is attributed to be due to the nano-ionics mechanism proposed by Maier and coworkers.Cyclic voltammetry and constant current charge-discharge performance were examined for the surface modified samples in view of power capability. The oxides of Ag, Cu, Pd, and Sn were found effective to enhance the capacitance and high rate charge/discharge performance. The cycleability test was performed as well.     

Distribution of radionuclides in surface seawater obtained by an aerial radiological survey

We investigated the distribution in seawater of anthropogenic radionuclides from the Fukushima Daiichi Nuclear Power Plant (FNPP1) as preliminary attempt using a rapid aerial radiological survey performed by the U.S. Department of Energy National Nuclear Security Administration on 18 April 2011. We found strong correlations between in-situ activities of ¹³¹I, ¹³⁴Cs, and ¹³⁷Cs measured in surface seawater samples and gamma-ray peak count rates determined by the aerial survey (correlation coefficients were 0.89 for ¹³¹I, 0.96 for¹³⁴Cs, and 0.92 for¹³⁷Cs). The offshore area of high radionuclide activity extended south and southeast from the FNPP1. The maximum activities of ¹³¹I, ¹³⁴Cs, and ¹³⁷Cs were 329, 650, and 599 Bq L^?1, respectively. The ¹³¹I/¹³⁷Cs ratio in surface water of the high-activity area ranged from 0.6 to 0.7. Considering the radioactive decay of ¹³¹I (half-life 8.02 d), we determined that the radionuclides in this area were directly released from FNPP1 to the ocean. We confirm that aerial radiological surveys can be effective for investigating the surface distribution of anthropogenic radionuclides in seawater. Our model reproduced the distribution pattern of radionuclides derived from the FNPP1, although results simulated by a regional ocean model were underestimated.     

Influence of extrusion temperature on molecular architecture and crystallization behavior of peroxide‐induced slightly crosslinked poly(L‐lactide) by reactive extrusion

The influence of temperature during reactive extrusion of poly(L ‐lactide) (PLLA) on the molecular architecture and crystallization behavior was investigated for OO‐(t‐butyl) O‐(2‐ethylhexyl) peroxycarbonate‐modified polymer. The long chain–branched PLLA (LCB‐PLLA) content and its structure in the resulting slightly crosslinked PLLA (χ‐PLLA) containing linear and LCB‐PLLA were characterized by both analyses, size exclusion chromatography equipped with multiangle laser light scattering and rheological measurements. A reduction of LCB‐PLLA content in χ‐PLLA and an increase of number of branches in LCB‐PLLA were found with increasing the extrusion temperature. An increase of extrusion temperature induces different process in the polymer: decrease of the lifetime of peroxide, increase of the radical concentration due to rapid peroxide decomposition rate, and increase of the chain diffusion to the amorphous phase. Among these indices, the lifetime of peroxide is a good index for crosslinking behavior of PLLA during extrusion. As for the isothermal crystallization behavior from the melt, the Avrami crystallization rate constant of χ‐PLLA increases as an increase of LCB‐PLLA content in χ‐PLLA. This implies that LCB‐PLLA acts as a nucleating agent for PLLA. Furthermore, regime analysis and the free energy of nucleus of χ‐PLLA were investigated using Hoffman–Lauritzen theory. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Importance of personal dose equivalent evaluation in Fukushima in overcoming social panic

The relationship between the reported ambient dose equivalent (H*(10)) and the individual dose rate recorded by medical staff in Fukushima City after the accident at the Fukushima Daiichi nuclear power plant was evaluated, following a 9.0-magnitude earthquake that struck the east coast of Japan. Personal dose equivalent (H(p)(10)) ranged from 0.08 to 1.63 μSv h(-1) and H*(10) ranged from 0.86 to 12.34 μSv h(-1). H(p)(10) from March to July 2011 were significantly lower than H*(10). The relationships between these dose equivalents were moderately correlated. The regression equation was calculated as follows: H(p)(10)=0.0696×H*(10)+0.0538. The preliminary data of this study show that, in Fukushima, the individual dose is much lower than that determined H*(10). It is important to evaluate H(p)(10) in order to lessen the anxiety of the general population in Fukushima.     

Application of high‐pressure swing adsorption process for improvement of CO2 recovery system from flue gas

Although the super cold separator applied to the system for CO₂ recovery from flue gas can produce pure CO₂ liquid, the CO₂ recovery efficiency is low. Therefore, the addition of a PSA plant was considered for the secondary CO₂ recovery from the noncon‐densing gas to improve the efficiency. The PSA plant was operated for adsorption at the same pressure as that of the super cold separator and for desorption at the atmospheric pressure. From both the simulation and the experimental data, it was confirmed that CO₂ could be concentrated from 50% in the noncondensing gas to 70% in the recovery gas by the PSA plant and the CO₂ recovery efficiency of the plant was about 90%.     

Longwave radiation flux from an urban canopy: Evaluation via measurements of directional radiometric temperature

Longwave radiation flux, an important part of the surface heat budget, is generally represented by εσT_r⁴, where ε is the surface emissivity, σ is the Stefan-Boltzmann constant, and T_r is the measured radiometric temperature. εσT_r⁴ differs from hemispheric emission because the measured radiometric temperature is anisotropic for an uneven surface. This paper analyzes the anisotropy-related error in measurements of longwave radiation flux from a building canopy. The flux difference between εσT_r⁴ and directly measured flux was up to 8% of the directly measured flux, which could be greater than the typical error in measurement of turbulent heat flux over a building canopy. The flux difference increased as the temperature variation within the urban street canyon increased, and also with increasing difference between the incident solar radiation of the building walls and street canyon floors (pavement, roads, ground surface). Theoretical calculations indicate that the flux difference is due to the structure of the building canopy and the temperature difference between the walls and canopy floors. A numerical model of a building canopy heat budget shows that the flux difference increases as the street canyon aspect ratio increases.     

Effect of moisture sorption of underwear material on clothing microclimate in a hot environment

In this study, to investigate the thermal comfort of underwear, it was experimentally evaluated how the moisture sorption of underwear material affected the transient condition on the clothing microclimate under the summer heat environment by using a perspiration thermal manikin. Three kinds of underwear with different mixed spinning rates of moisture absorbing synthetic fiber (MAS) were compared. It was shown that the higher the mixed spinning rate of MAS, the larger the decline of the humidity in the clothing was in insensible perspiration. In comparison, for PET70 with 100% cotton (COT100), though each of the official moisture regions was almost the same, the microclimate humidity declined more rapidly in COT100 and returned to the original humidity in a shorter time. The integration value of the humidity decline which returned to the original value was the same between the two materials. To show the effect of the initial condition of the material, the underwear in a moderate humid condition, which was 30^°C, 65% RH, was compared with one in a dry condition. The fall in the clothing microclimate of the humid condition was about one third that of the dry one. In sensible perspiration, though the humidity decline was seen, it returned to the original humidity faster than in the insensible condition. A temperature rise in the clothing and a temperature drop occurred as frequently as in the standard underwear during drying on the skin surface. This suggested that the endothermic reaction occurred as moisture desorbed. © 2008 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20220