Positronium bubble oscillation in room temperature ionic liquids

Positronium bubble oscillation before the stabilization of the bubble was successfully observed by the change of the triplet Ps (ortho-Ps) pick-off annihilation rate in a room temperature ionic liquid, N,N,N-trimethyl-N-propylammonium bis(trifluoromethanesulfonyl)imide (TMPA-TFSI). It was re-ported that the Ps bubble stabilization in TMPA-TFSI took more than 500 ps. For materials having Ps formation, singlet Ps (para-Ps) gives the fastest annihilation mean lifetime of about 125 ps. Although it is intrinsic annihilation, the Ps bubble oscillation affects the para-Ps annihilation rate. The oscil-lation on the ortho-Ps pick-off annihilation was expected to appear at positron ages older than about 400 ps after the para-Ps annihilation fraction becomes small enough. An oscillation with 5.85 GHz frequency of the ortho-Ps pick-off annihilation rate was successfully observed at the positron ages older than 500 ps in 25 ◦C TMPA-TFSI. 1

Improved Approximation Lower Bounds for TSP with Distances One and Two

The metric travelling salesman problem Δ-Tsp is the traveling salesman problem in which the distances among cities satisfy the triangle inequality. In this paper, we consider the matric traveling salesman problem Δ(1,2)-Tsp with distances one and two and Δ(1,2,3)-Tsp with distances one, two, and three as the special cases of Δ-Tsp. Since Δ(1,2)-Tsp is NP-complete, it is NP-hard to find an optimal solution for Δ(1,2)-Tsp. So in polynomial time, we with to find an approximate solution for Δ(1,2)-Tsp. owever Δ(1,2)-Tsp is APX-complete, there is a nontrivial approximation lower bound for Δ(1,2)-Tsp. For any ε>0, Engebretsen showed that it is NP-hard to approximate the symmetric Δ(1,2)-Tsp within 5381/5380-ε; the asymmetric Δ(1,2)-Tsp within 2805/2804-ε, and Bochenhauer, et al. showed that it is NP-hard to approximate the symmetric Δ(1,2,3)-Tsp within 3813/3812-ε. In this paper, we improve those lower bounds and show that for any ε>0, it is NP-hard to approximate the symmetric Δ(1,2)-Tsp within 1027/1026-ε (Corollary 4.5); the asymmetric Δ(1,2)-Tsp within 535/534-ε (Corollary 4.7); the symmetric Δ(1,2,3)-Tsp within 817/816-ε (Theorem 5.2); the asymmetric Δ(1,2,3)-Tsp within 364/363-ε (Theorem 5.3). We also show that for any ε>0, it is NP-hard to approximate Shortest-Superstring within 1279/1278-ε (Corollary 6.3)

The role of positronium decoherence in the studies of positron annihilation in matter

A small difference between the energy of the para-positronium (p-Ps) and ortho-positronium (o-Ps) states suggests the possibility of superposition of p-Ps and o-Ps during the formation of positronium (Ps) from pre-Ps terminating its migration in the matter in a void ('free volume'). It is shown that such a superposition decohere in the basis of p-Ps and o-Ps and the decoherence time is estimated. The time scale of the decoherence estimated here motivates respective correction in decomposition of the positron annihilation lifetime spectra. The way of the correction is sketched. The timescale of the decoherence suggests a need of awareness when experimental data from positron annihilation techniques are processed. More generally, the superposited state of Ps should contribute to the evolution theory of positronium in matter.Comment: 15 pages, 6 figure

Molecular Interaction Between the Microenvironment and FLT3/ITD+ AML Cells Leading to the Refractory Phenotype

Internal tandem duplication mutations in the FLT3 gene (FLT3/ITD) are detected in 10–15% of children and 30% of adult patients with AML and are associated with an extremely poor prognosis. Although several antagonists against FLT3/ITD have been developed, few of them are effective for the treatment of FLT3/ITD+ AML because of the emergence of drug-resistant cells. The mechanisms responsible for drug resistance include the acquisition of additional mutations in the FLT3 gene and/or activation of other prosurvival pathways such as microenvironment-mediated resistance. Recent studies have strongly suggested that the reciprocal interaction between the microenvironment and AML cells generates specific machinery that leads to chemoresistance. This chapter describes the molecular mechanism responsible for the refractory phenotype of FLT3/ITD+ AML cells resulting from the communication between the microenvironment and FLT3/ITD+ leukemia cells. Understanding this mechanism enables the discovery of novel and innovative therapeutic interventions for resistant FLT3/ITD+ AML

Precise and Efficient Nucleotide Substitution Near Genomic Nick via Noncanonical Homology-Directed Repair

CRISPR/Cas9, which generates DNA double-strand breaks (DSBs) at target loci, is a powerful tool for editing genomes when codelivered with a donor DNA template. However, DSBs, which are the most deleterious type of DNA damage, often result in unintended nucleotide insertions/deletions (indels) via mutagenic nonhomologous end joining. We developed a strategy for precise gene editing that does not generate DSBs. We show that a combination of single nicks in the target gene and donor plasmid (SNGD) using Cas9D10A nickase promotes efficient nucleotide substitution by gene editing. Nicking the target gene alone did not facilitate efficient gene editing. However, an additional nick in the donor plasmid backbone markedly improved the gene-editing efficiency. SNGD-mediated gene editing led to a markedly lower indel frequency than that by the DSB-mediated approach. We also show that SNGD promotes gene editing at endogenous loci in human cells. Mechanistically, SNGD-mediated gene editing requires long-sequence homology between the target gene and repair template, but does not require CtIP, RAD51, or RAD52. Thus, it is considered that noncanonical homology-directed repair regulates the SNGD-mediated gene editing. In summary, SNGD promotes precise and efficient gene editing and may be a promising strategy for the development of a novel gene therapy approach

How did OHNISHI Hajime receive Kant\u27s philosophy?

Early in the Meiji era, Japan emphasized "practical science". As a result, utilitarianism and positivism were regarded as a highly timely and the thinkers of The Meiji 6 Society (Meirokusha) taught them eagerly. They made an effort to allow the Japanese to these academic positions. However, come to the middle of the Meiji era, students started to learn German philosophy and its idealistic and spiritual way of thinking in the University of Tokyo. These new thoughts gradually prevailed among Japanese thinkers. OHNISHI Hajime (1864-1900) is a representative thinker of modern Japanese influenced by German philosophy. He developed his original ethical thought, which taught that the purpose of ethics was to find moral ideals for human beings. As is well known, OHNISHI is considered to be "Japanese Kant". This is because OHNISHI declared criticism as his fundamental thought. I report the impacts OHNISHI received from Kant, especially Kant\u27s moral philosophy.中谷伸生教授古稀記念

人間の尊厳概念の研究 : カントの道徳哲学と宗教論の統合的解釈

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