Tokiwa Park

DNA double-strand breaks (DSBs) are primarily repaired in eukaryotic cells through two pathways: homologous recombination (HR) and non-homologous end joining (NHEJ). The thermotolerant yeast Kluyveromyces marxianus is recognized for its highly active NHEJ pathway, making it a suitable model organism for studying the role of NHEJ in DSB repair. To induce DSBs in K. marxianus DMKU3-1042, an expression cassette containing the gene encoding the endonuclease RsaI was integrated into the LYS1 locus of both the wild-type and NHEJ-deficient KU70 mutant strains. This cassette is regulated by the galactose-inducible promoter GAL10. Cells expressing RsaI and grown in galactose medium exhibited an elongated, rod-shaped morphology under a microscope. Following RsaI expression, the viability of transformed KU70 cells decreased during the first three hours of culture in liquid medium and then partially recovered after six hours of incubation. In contrast, the KU70 mutant cells failed to produce viable survivors. Pulsed-field gel electrophoresis analysis revealed distinct chromosomal separation patterns among various RsaI-transformed KU70 cells. These findings demonstrate that the repair of RsaI-induced DSBs in K. marxianus DMKU3-1042 results in new strains with several forms of rearranged chromosomes.

Abstract γ-Hydroxy-α,β-unsaturated ammonium salts were easily prepared from diol-ammonium salts by treatment with dimethyl carbonate and potassium carbonate at 75 °C. Dehydration progressed smoothly under very mild conditions. The presence of the diol unit is crucial for the smooth dehydration; monoalcohol derivatives failed this conversion.

An OER catalyst was developed by ball milling todorokite-type δ-MnO2 manganese nodules, and its catalytic activity was investigated using operando XAFS to elucidate structure–activity relationships.

This paper presents the first attempt at establishing the dynamics of the Šumljak debris slide by using a multidisciplinary approach, including long-term inclinometer and piezometer measurements and a time-series analysis of SAR images for displacement vector estimation. The Šumljak landslide is located in the Rebrnice area, SW Slovenia, where the regional highway Razdrto-Nova Gorica runs through and poses a threat to the highway viaduct’s stability. By combining both ascending and descending Sentinel-1 data, we have estimated 3D displacement vectors for the landslide, providing insights into the usability of the technique for this kind of slow-moving landslides. Furthermore, we have combined and compared the SBAS DInSAR results to the displacements measured by inclinometer to evaluate the rate of displacement of the landslide and the viaduct. The inclinometer measurement results show that the landslide has a single sliding plane between the flysch colluvium and the slope deposits and provide the proof of the enlargement of the sliding area above its main scarp. The displacement vectors are spatially heterogenous, suggesting that different sites have different velocities and slightly different directional vectors. These results partly comply with the InSAR results. We further discussed the estimated vectors of displacement and the possible mechanism of movements. By using the piezometric data, we studied the groundwater level fluctuation in relation to daily rainfall and its influence on the displacements. Our findings show a correlation between the movements and the wet/dry season, indicating that the landslide is driven by rainfall and consequently groundwater level fluctuation. In 2020, the groundwater level rise was smaller than in the years before due to less rainfall, resulting in lower velocity of the landslide (5.5 mm/year) than in 2019 (7 mm/year).

In quantum mechanics it is well known that observables are represented by hermitian matrices (or operators). Uncertainty relations are represented as some kinds of trace inequalities satisfied by two observables and one density matrix (or operator). By releasing the hermitian restriction on observables, we obtained non-hermite uncertainty relations. In this paper we give several non-hermitian extensions of Heisenberg or Schrödinger type q uncertainty relations for generalized skew information under some conditions.

Stimulated emission properties of AlGaN‐based multiple quantum wells with an emission wavelength of about 280 nm are studied by photoluminescence excitation (PLE) spectroscopy. The excitation power density dependence of the PLE spectra is evaluated at excitation energies from 4.4788 to 4.6293 eV, which allows the spontaneous and stimulated emission PLE spectra to be obtained. A clear peak is observed in the PLE spectrum for spontaneous emission, indicating that the spontaneous emission is due to the excitonic optical transition. A clear peak is also observed in the PLE spectrum for stimulated emission, suggesting that excitons are involved in the stimulated emission process. Furthermore, the threshold excitation power density for stimulated emission is analyzed as a function of the excitation energy and the threshold excitation power density depends on the excitation energy. The excitation energy at which the threshold excitation power density is minimized agrees with the peak of the stimulated emission PLE spectrum. This observation directly indicates that excitons are important in optical gain formation.

It is well known that the transverse cracks (TCs) generated in CFRP laminates are saturated, and the number of saturated TCs varies widely. This paper presents a stochastic approach for the TC saturation characteristics cumulated in a CFRP cross-ply laminate under tensile loading. An inverse analysis mechanics model was proposed on the basis of Markov process combined with a matrix cracking model which was derived on the basis of slow crack growth (SCG) concept in conjunction with the Weibull distribution. The analysis model is assumed that each discrete stage is assigned in the order of the TCs generation, and that it transits to two states i.e., continuously generated and saturated states from one state. The saturated TCs data was stochastically analyzed using the analysis model. The estimated TC saturation probability curves approached the experimentally obtained saturation TCs data with an increase in the number of TCs and ultimately agreed with them. The measured and estimated mean number of saturated TCs was in good agreement.

近年，サンゴ礁は気候変動と人間活動が引き起こす攪乱要因によってサンゴの被度，サンゴ礁の面積が減少傾向にある。一方で近年の海水準上昇がサンゴ礁の成長を促している例も報告されており，今後もサンゴ礁が形成されるのか関心が高まっている。本稿ではまず，サンゴ礁形成過程を復元するために重要となる掘削試料および離水サンゴ礁での研究方法をまとめた。また，サンゴ礁形成過程においてサンゴの属名と群体形が注目されていたが，サンゴ礁形成においてサンゴ種（鍵種）も重要な役割を持っている可能性が明らかとなってきた。しかし，鍵種に注目した研究例が少ない点や鍵種の同定方法など解決すべき課題が多いことも明らかとなってきた。今後，サンゴ礁の将来予測を行うには，サンゴ礁形成に関わる条件を詳細に明らかにすることや，サンゴ等の被度のモニタリングに加えて，サンゴ礁の上方成長速度と海面上昇速度もモニタリングしていくことが不可欠である。

Cobalt oxyhydroxide (CoOOH) electrocatalysts with a hemispherical cavity structure were electrodeposited in borate-buffered solution using a polystyrene colloidal template method. The hemispherical-cavity catalysts exhibited higher activity for the oxygen evolution reaction than the corresponding flat thin-film catalysts. Analysis by operando Co K-edge X-ray absorption spectroscopy revealed that, under the electrode working conditions, the local structure of the Co species was composed of nanosized CoOOH clusters with high-oxidation-number Co species. In addition, a B K-edge X-ray absorption spectroscopic analysis showed that borate anions were adsorbed onto the catalysts, stabilizing the catalyst structure. Thus, the highly oxidized CoOOH clusters with adsorbed borate anions are likely to function as active sites, possibly because the clusters are generated around anisotropic Co sites in the catalysts with hemispherical cavities. Cobalt oxyhydroxide (CoOOH) electrocatalysts with a hemispherical cavity structure were electrodeposited in borate-buffered solution using a polystyrene colloidal template method. The hemispherical-cavity catalysts exhibited higher activity for the oxygen evolution reaction than the corresponding flat thin-film catalysts.