Beside the double helix structure, circular DNA molecules may be knotted or linked. Two interlinked DNA molecules arise during process of replication. They have to be unlinked to allow the separation ...of the two daughter molecules during cell division. Type II topoisomerases and site-specific recombinases can solve such topological entanglement problems of DNA molecules. We will discuss topological characterizations of the enzyme action using knot theory.
Abstract
The recently discovered kagome superconductors
A
V
3
Sb
5
(
A
= K, Rb, Cs) exhibit unusual charge-density-wave (CDW) orders with time-reversal and rotational symmetry breaking. One of the ...most crucial unresolved issues is identifying the symmetry of the superconductivity that develops inside the CDW phase. Theory predicts a variety of unconventional superconducting symmetries with sign-changing and chiral order parameters. Experimentally, however, superconducting phase information in
A
V
3
Sb
5
is still lacking. Here we report the impurity effects in CsV
3
Sb
5
using electron irradiation as a phase-sensitive probe of superconductivity. Our magnetic penetration depth measurements reveal that with increasing impurities, an anisotropic fully-gapped state changes to an isotropic full-gap state without passing through a nodal state. Furthermore, transport measurements under pressure show that the double superconducting dome in the pressure-temperature phase diagram survives against sufficient impurities. These results support that CsV
3
Sb
5
is a non-chiral, anisotropic
s
-wave superconductor with no sign change both at ambient and under pressure.
Quasi-static magnetic-fields up to 800 T are generated in the interaction of intense laser pulses (500 J, 1 ns, ) with capacitor-coil targets of different materials. The reproducible magnetic-field ...peak and rise-time, consistent with the laser pulse duration, were accurately inferred from measurements with GHz-bandwidth inductor pickup coils (B-dot probes). Results from Faraday rotation of polarized optical laser light and deflectometry of energetic proton beams are consistent with the B-dot probe measurements at the early stages of the target charging, up to ns, and then are disturbed by radiation and plasma effects. The field has a dipole-like distribution over a characteristic volume of 1 mm3, which is consistent with theoretical expectations. These results demonstrate a very efficient conversion of the laser energy into magnetic fields, thus establishing a robust laser-driven platform for reproducible, well characterized, generation of quasi-static magnetic fields at the kT-level, as well as for magnetization and accurate probing of high-energy-density samples driven by secondary powerful laser or particle beams.
This paper describes a novel regenerative braking control scheme of electric power-assisted wheelchairs for safety driving on downhill roads. The ldquoelectric power-assisted wheelchairrdquo which ...assists the driving force by electric motors is expected to be widely used as a mobility support system for elderly people and disabled people; however, it has no braking system to suppress the wheelchair's velocity and brings the dangerous and fearful driving particularly on downhill roads. Therefore, this paper proposes a novel safety and efficient driving control scheme based on the regenerative braking system. This paper applies the regenerative braking system with the step-up chopper circuit serially connecting two motors and realizes the velocity feedback control with the variable duty ratio so that it tracks the optimal velocity based on the minimum Jerk model. In addition, the dynamic braking system is also applied at the low-speed range instead of the regenerative braking in order to suppress the acceleration. Some driving experiments on the practical downhill roads show the effectiveness of the proposed control system.
A near‐future, 2‐K warming climate simulation comprising over 3,000 years of ensemble simulations was performed using 60‐km global and 20‐km regional atmospheric models. Even in the +2‐K climate, ...indices of extreme precipitation and dryness increased significantly in the extratropics compared with the historical climate. Mean precipitation increases in the rainy season and decreases in the dry season, indicating that the seasonal precipitation range becomes amplified with global warming. The intensification of precipitation and dryness from +2 to +4 K was also robust in the mean for climatological wet and arid regions. Around Japan, which was classified as a wet region, the regional atmospheric model predicts that the extreme hourly precipitation in the future climate becomes more extreme on hot days, but slightly weaker on cold days. This extreme precipitation has a high sensitivity to air temperature exceeding 7%/K.
Plain Language Summary
Our study shows the precipitation changes in the near‐future around the 2040s, +2‐K climate. Even in the +2‐K climate, both extreme precipitation and dryness in the extratropics increase significantly. These results urge to plan for adaptation to extreme weather in the near future. The 2‐K warming climate simulation was performed with over 3,000 years of ensemble member using 60‐km global and 20‐km regional atmospheric models. A large number of ensemble data elucidated statistically significant increment of the precipitation extremes, moreover the amplifying of the seasonal precipitation range. The data are helpful to investigate the climate in the near‐future containing mixed uncertainty both internal variation and effects of future scenario. It would provide valuable information for policy‐making, planning of mitigation, and adaptation for extreme weather events, such as flooding or droughts in the near‐future climate.
Key Points
High‐resolution large‐ensemble simulations are performed to assess precipitation change under the +2‐K climate
Even in the +2‐K climate, both extreme precipitation and dryness in the extratropics increase significantly compared with the historical climate
The tendency for the seasonal precipitation range to amplify becomes robust with global warming from the +2‐K to +4‐K climate
In this paper, we present coherent optical single carrier transmission (COSC) using overlap frequency domain equalization (OFDE) for the chromatic dispersion (CD) compensation. Residual inter-symbol ...interference is suppressed by time domain equalization with small tap size. In single polarization transmission, 25-Gb/s COSC transmission with OFDE is demonstrated over 800 km to 4320 km of single-mode fiber (SMF) without optical dispersion compensation. The measured results show that the proposed configuration improves the transmission performance by setting adequate overlapped size of FFT windows and that it is suitable for long-haul optical communication systems.
Interleukin (IL)-6 is a pleiotropic cytokine that not only affects the immune system, but also acts in other biological systems and many physiological events in various organs. In a target cell, IL-6 ...can simultaneously generate functionally distinct or sometimes contradictory signals through its receptor complex, IL-6Ralpha and gp130. One good illustration is derived from the in vitro observations that IL-6 promotes the growth arrest and differentiation of M1 cells through gp130-mediated STAT3 activation, whereas the Y759/SHP-2-mediated cascade by gp130 stimulation has growth-enhancing effects. The final physiological output can be thought of as a consequence of the orchestration of the diverse signaling pathways generated by a given ligand. This concept, the signal orchestration model, may explain how IL-6 can elicit proinflammatory or anti-inflammatory effects, depending on the in vivo environmental circumstances. Elucidation of the molecular mechanisms underlying this issue is a challenging subject for future research. Intriguingly, recent in vivo studies indicated that the SHP-2-binding site- and YXXQ-mediated pathways through gp130 are not mutually exclusive but affect each other: a mutation at the SHP-2-binding site prolongs STAT3 activation, and a loss of STAT activation by gp130 truncation leads to sustained SHP-2/ERK MAPK phosphorylation. Although IL-6/gp130 signaling is a promising target for drug discovery for many human diseases, the interdependence of each signaling pathway may be an obstacle to the development of a nonpeptide orally active small molecule to inhibit one of these IL-6 signaling cascades, because it would disturb the signal orchestration. In mice, a consequence of the imbalanced signals causes unexpected results such as gastrointestinal disorders, autoimmune diseases, and/or chronic inflammatory proliferative diseases. However, lessons learned from IL-6 KO mice indicate that IL-6 is not essential for vital biological processes, but a significant impact on disease progression in many experimental models for human disorders. Thus, IL-6/gp130 signaling will become a more attractive therapeutic target for human inflammatory diseases when a better understanding of IL-6 signaling, including the identification of the conductor for gp130 signal transduction, is achieved.
Objective
In the gingival crevice, the interaction between epithelial cells and periodontopathic bacteria is important for the development of periodontitis. Treponema denticola is a major pathogen of ...chronic periodontitis and possesses several virulence factors, such as major surface protein (Msp) and prolyl‐phenylalanine‐specific protease (dentilisin). Here, we investigated the behaviours of epithelial cells infected with T. denticola by measuring the expression of interleukin (IL)‐1β, IL‐6, β defensin 2 (BD‐2) and heat‐shock protein 70 (HSP70).
Methods
Epithelial cells were infected with T. denticola wild‐type strain, Msp‐deficient mutant or dentilisin‐deficient mutant, and the expression levels of the above targets were analysed by polymerase chain reaction.
Results
Infection with T. denticola wild‐type strain and mutants induced the production of IL‐6 and HSP70. The level of BD‐2 induced by T. denticola wild‐type strain at 24 hr was significantly higher than that of the dentilisin‐deficient mutant. The level of IL‐1β mRNA in the wild‐type strain and dentilisin‐deficient mutant was slightly lower than that in the uninfected control.
Conclusion
These results suggest that the levels of BD‐2 were affected by Msp and dentilisin. This effect may contribute to the disruption of the response of epithelial cells to eradicate T. denticola.
PDF
