Electron-capture decay rate of ⁷Be encapsulated in a C₇₀ fullerene cage

The decay rate of ⁷Be electron capture in C₇₀ and Be metal was measured employing a reference method. The half-life (T_{1/2}) of ⁷Be endohedral C₇₀ (⁷Be@C₇₀) was found to be T_{1/2} = 52.49±0.04 d at room temperature (T = 293 K) and T_{1/2} = 52.42±0.04 d at liquid helium temperature (T = 5 K). Furthermore, the T_{1/2} of ⁷Be in Be metal was T_{1/2} = 53.25±0.04 d at room temperature (T = 293 K) and T_{1/2} = 53.39±0.03 d at liquid helium temperature (T = 5 K). These values for ⁷Be@C₇₀ at T = 5 K are approximately 1.6%(1.8%) smaller than those for ⁷Be in Be metal at T = 293 K (T = 5 K), indicating the difference in the electron wave functions for ⁷Be inside C₇₀ and ⁷Be in C60 and Be metal. The average charge transfer from the L(2s) electrons of the ⁷Be atom influences such variations in the decay constant (λ = ln2/T_{1/2}) in the environment. The experimental and theoretical investigations revealed that the change in the EC-decay rate of ⁷Be could be largely related to the potential configurations and the environment inside C60 and/or C₇₀ cages. The motion of ⁷Be inside cages was found to be restricted according to temperature

ComPARAFAC: a library and tools for rapid and quantitative comparison of dissolved organic matter components resolved by Parallel Factor Analysis.

Parallel Factor Analysis (PARAFAC) is a well-established method for characterizing dissolved organic matter (DOM). While methods for sample processing and PARAFAC analysis are well defined and robust, subsequent classification of DOM fluorescence components and comparisons of components among studies remain highly qualitative. Because these comparisons often guide the interpretation of subsequent data, it is important that quantitatively accurate comparisons be made. We developed a statistical tool, comPARAFAC, using a modified Tucker’s Congruence Coefficient (mTCC), an established method of factor comparison, to provide a quantitative basis for comparing models. To develop and test this tool we used mTCC to compare factors from 35 DOM fluorescence studies using Parallel Factor Analysis (PARAFAC) in marine and freshwater environments. We compared mTCCguided component matching with qualitative comparisons made in the literature to describe the current perceptions of component equivalence. Based on our analysis, 21% of the direct comparisons made using the qualitative approach are potentially erroneous, whereas possible matches are missed 14% of the time using that same approach. The procedure and accompanying PARAFAC model library for performing quantitative mTCC-guided comparisons are available as an R package (see Web Appendix A). This method simplifies and standardizes the process by which researchers identify and compare fluorescent DOM components across studies

Life-time measurement of ^7Be in beryllium metal(II. Radiochemistry)

The decay rate of ^7Be (nucleus of electron-capture decay) was measured in Be metal. The half life of ^7Be in Be metal (Be metal (^7Be)) is found to be 53.12±0.05 days. We have found that the decay rate of ^7Be in Be metal is almost corresponding to that in graphite host, Lithium fluoride host etc. reported within the errors

Transcripts expressed using a bicistronic vector pIREShyg2 are sensitized to nonsense-mediated mRNA decay

<p>Abstract</p> <p>Background</p> <p>pIREShyg2 has been widely used as a bicistronic expression vector. However, it is not known if the vector would affect the expression of cloned genes via nonsense-mediated mRNA decay (NMD), an mRNA surveillance system that degrades mRNA with a premature termination codon (PTC). In mammalian cells, the induction of NMD requires either a long 3'UTR or the presence of an exon-junction complex downstream of a PTC. The efficiency of NMD is greater when a PTC generates longer 3'UTR. pIREShyg2 provides the first cistron gene with a long 3'UTR consisting of a downstream intervening sequence (IVS), an internal ribosomal entry site (IRES) and the second cistron. Therefore, we hypothesized that the first cistron genes in pIREShyg2 are sensitized to NMD, which affects their expression levels. To examine this hypothesis, cDNAs encoding human granulocyte-macrophage colony-stimulating factor receptor β chain (βc) and its splice variant (βc79), in which the retention of a 79-base intron caused a frameshift generating 18 PTCs, were cloned into pIREShyg2 and stably expressed in a murine cell line, Ba/F3.</p> <p>Results</p> <p>Compared with wild-type βc, the mRNA levels of βc79 were less than one tenth and decayed faster. Both translation inhibition and Upf1 knockdown led to significantly greater up-regulation of βc79 than wild-type βc. However, the use of a monocistronic pMT21 vector abolished the up-regulatory effects of translation inhibition and Upf1 knockdown on both wild-type βc and βc79, suggesting that the NMD is attributable to a structural determinant in pIREShyg2. The elimination of the intron and the proximal 3' 17 PTCs did not alter the greater effects of translation inhibition on βc79, suggesting that the first PTC, which determines 3'UTR length, was sufficient to enhance NMD efficiency. Thus, transcripts of PTC-harboring genes with longer 3'UTR are more efficiently degraded by the vector-dependent NMD than those of wild-type genes with relatively shorter 3'UTR, resulting in minimized expression of truncated mutants.</p> <p>Conclusions</p> <p>We conclude that pIREShyg2, which sensitizes its bicistronic transcripts to NMD, may be useful for studying NMD but should be avoided when maximum expressions of PTC-harboring genes are required.</p

Creation of Mo/Tc@C60 and Au@C60 and molecular-dynamics simulations

The formation of middle- and/or high-weight atom (Mo, Au)-incorporated fullerenes was investigated using radionuclides produced by nuclear reactions. From the trace radioactivities of ⁹⁹Mo/⁹⁹mTc or ¹⁹⁴Au after high-performance liquid chromatography, it was found that the formation of endohedral and/or heterofullerene fullerenes in ⁹⁹Mo/⁹⁹mTc and ¹⁹⁴Au atoms could occur by a recoil process following the nuclear reactions. Furthermore, the ⁹⁹mTc (and ¹⁹⁴Au) atoms recoiled against β-decay remained present inside these cages. To confirm the produced materials experimentally, ab initio molecular dynamics (MD) simulations based on an all-electron mixed-basis approach were performed. The possibility of the formation of endohedral fullerenes containing Mo/Tc and Au atoms is verified; here, the formation of heterofullerenes is excluded by MD simulations. These findings suggest that radionuclides stably encapsulated by fullerenes could potentially play a valuable role in diagnostic nuclear medicine

Versatile strategy using vaccinia virus-capping enzyme to synthesize functional 5′ cap-modified mRNAs

様々な5'キャップ構造をもつ機能的なmRNAの汎用的な合成方法 酵素を用いて簡便かつ効率的に. 京都大学プレスリリース. 2023-02-03.Development of a versatile method to synthesize functional mRNAs with diverse 5' cap structures. 京都大学プレスリリース. 2023-02-03.The potential of synthetic mRNA as a genetic carrier has increased its application in scientific fields. Because the 5′ cap regulates the stability and translational activity of mRNAs, there are concerted efforts to search for and synthesize chemically-modified 5′ caps that improve the functionality of mRNA. Here, we report an easy and efficient method to synthesize functional mRNAs by modifying multiple 5′ cap analogs using a vaccinia virus-capping enzyme. We show that this enzyme can introduce a variety of GTP analogs to the 5′ end of RNA to generate 5′ cap-modified mRNAs that exhibit different translation levels. Notably, some of these modified mRNAs improve translation efficiency and can be conjugated to chemical structures, further increasing their functionality. Our versatile method to generate 5′ cap-modified mRNAs will provide useful tools for RNA therapeutics and biological research

Structure analysis of Zn-Mg-Ho icosahedral quasicrystal by modified Rietveld method using ellipsoid and sphere windows

A structure analysis of Zn-Mg-Ho icosahedral quasicrystal was carried out by the powder X-ray diffraction method using synchrotron radiation (Lambda=0.73490 A) at SPring-8. The intensity distribution was analyzed by the Rietveld method modified for an icosahedral quasicrystal, in which simplified models were assumed: ellipsoid and spherical windows were assumed at five crystallographic sites in a F-type hypercubic unit cell. The analysis revealed the presence of an almost perfect Penrose tiling with edge length 5.20 A. The vertices are occupied alternatively by Zn and Mg, and almost all of the edge centers of the Penrose rhombohedra are occupied by 0.8Zn and 0.2Mg. Ho and Mg atoms tend to be present on the body diagonal of the prolate rhombohedra. Good agreement between the measured and calculated intensity distribution using the simplified model suggests the applicability and the limitation of structure analysis using the powder X-ray diffraction method.Comment: 10 pages, 3 tables, 3 figure

Heart Disease Mortality in Cancer Survivors: A Population-Based Study in Japan

BACKGROUND: Data on the risk of cardiovascular-related mortality in patients with cancer are limited. METHODS AND RESULTS: This retrospective cohort study used data from the Osaka Cancer Registry and vital statistics in Japan between 1985 and 2013. The causes of death were investigated, and the risk of fatal heart disease was analyzed. Standardized mortality ratios were calculated to compare the risk of fatal heart disease between patients with cancer and the general population. Fine and Gray competing risk regression models were used to assess the risk of fatal heart disease among patients with cancer. In total, 682 886 patients with cancer were included in the analysis, and 335 635 patients died during the study period. Heart disease was the leading cause of noncancer deaths, with 10 686 deaths. Among the patients who died of heart disease, 5017 had ischemic heart disease, 3598 had heart failure, 356 had hypertensive disease, and 1715 had other heart diseases. The standardized mortality ratio for heart disease was 2.80 (95% CI, 2.74-2.85). The standardized mortality ratio for ischemic heart disease, heart failure, and hypertensive disease were 3.26 (95% CI, 3.17-3.35), 2.69 (95% CI, 2.60-2.78), and 5.97 (95% CI, 5.38-6.63), respectively. The risk of fatal heart disease increased over time after cancer diagnosis. Men were more likely to die of heart disease than women (subdistribution hazard ratio, 1.08 [95% CI, 1.02-1.16]). The risk of fatal heart disease among cancer survivors has decreased in recent years. CONCLUSIONS: Cancer survivors have a higher risk of fatal heart disease than the general population.Gon Y., Zha L., Sasaki T., et al. Heart Disease Mortality in Cancer Survivors: A Population-Based Study in Japan. Journal of the American Heart Association 12, e029967 (2023); https://doi.org/10.1161/JAHA.123.029967