Electron beam-induced white emission from iridium complexes-doped polymer dots

The version of record of this article, first published in Photochemical and Photobiological Sciences, is available online at Publisher’s website: https://doi.org/10.1007/s43630-023-00520-3Radiation detection plays an important role in diverse applications, including medical imaging, security, and display technologies. Scintillators, materials that emit light upon exposure to radiation, have garnered significant attention due to their exceptional sensitivity. Previous research explored polymer dots (P-dots) doped with iridium complexes as nano-sized scintillators for radiation detection, but these were constrained to emitting specific colors like red, green, and blue, limiting their utility. Recently, there has been a breakthrough in the development of white light emitters stimulated by UV–visible light. These emitters exhibit a broad spectral range in the visible wavelength, enhancing contrast and simplifying detection by visible-light sensors. Consequently, the quest for white color scintillators in radiation detection has emerged as a promising avenue for enhancing scintillation efficiency. In this study, we present a novel approach by applying P-dots doped with two iridium complexes to create white light-emitting nano-sized scintillators. These scintillators offer a wider spectral coverage within the visible-light wavelength range. Under UV light (365 nm) excitation, our synthesized P-dots exhibited remarkable white light emission. Moreover, when excited by electron beam irradiation, we observed the clear emission close to white emission which is valuable for improving the detection of radiation

Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples

Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts

Mesolysis of Radical Anions of Tetra‑, Penta‑, and Hexaphenylethanes

A central carbon–carbon (C–C) σ bond dissociation of polyphenylethane radical anions (Ph_<i>n</i>E^•‑, <i>n</i> = 3–6), mesolysis, was investigated by the transient absorption measurement during pulse radiolysis of Ph_<i>n</i>E in 2-methyltetrahydrofuran. The charge resonance (CR) band of 1,1,2,2-tetraphenylethane radical anion (1,1,2,2-Ph₄E^•‑) was observed in the near-infrared region immediately after an electron pulse to be attributed to the intramolecular dimer radical anion. The CR band disappeared with simultaneous formation of two absorption bands at 330 and 460 nm corresponding to diphenylmethyl radical and diphenylmethyl anion, respectively, indicating the occurrence of the mesolysis in 1,1,2,2-Ph₄E^•‑. During pulse radiolysis of 1,1,1,2,2,2-hexaphenylethane (Ph₆E), an absorption band of triphenylmethyl radical was observed at 340 nm immediately after an electron pulse. It is suggested that one electron attachment to Ph₆E is followed by the subsequent rapid C–C σ bond dissociation. Formation of intramolecular dimer radical anions in Ph_<i>n</i>E^•‑ such as 1,1,2-triphenylethane (Ph₃E), 1,1,1,2-tetraphenylethane (1,1,1,2-Ph₄E), and 1,1,1,2,2-pentaphenylethane (Ph₅E) was also studied together with the subsequent mesolysis. The mesolysis of Ph_<i>n</i>E^•‑ is discussed in terms of charge delocalization in the intramolecular dimer radical anions and the central C–C σ bond as well as bond dissociation energy of the central C–C σ bond of Ph_<i>n</i>E^•‑

Intramolecular Charge Resonance in Dimer Radical Anions of Di-, Tri-, Tetra-, and Pentaphenylalkanes

Intramolecular dimer radical anions of di-, tri-, tetra-, and pentaphenylalkanes were investigated on the basis of absorption spectral measurements during γ-radiolysis in 2-methyltetrahydrofuran (MTHF) glassy matrix at 77 K and theoretical calculations. The absorption spectrum of 1,1,2,2-tetraphenylethane (1,1,2,2-Ph₄E) radical anion showed two bands in the near-infrared (NIR) region (900–2600 nm). One band observed at shorter wavelength than 2000 nm is assigned to the intramolecular charge resonance (CR) band between two phenyl groups of the 1,1-diphenylmethyl chromophore (1,1-dimer radical anion). The intramolecular CR band of the 1,1-dimer radical anion was observed for various alkanes having 1,1-diphenylmethyl chromophore such as 1,1,1-triphenylmethane (1,1,1-Ph₃M), 1,1,1,1-tetraphenylmethane (1,1,1,1-Ph₄M), and so on. The other intramolecular CR band observed at longer wavelength than 2200 nm is assigned to intramolecular dimer radical anion between two phenyl groups of the 1,2-diphenylethyl chromophore (1,2-dimer radical anion). The intramolecular CR band of the 1,2-dimer radical anion was observed for various alkanes having a 1,2-diphenylethyl chromophore, such as 1,1,2-triphenylethane (1,1,2-Ph₃E), 1,1,2,2-Ph₄E, and 1,1,1,2,2-pentaphenylethane (1,1,1,2,2-Ph₅E) and so on. No dimer radical anion was observed for 1,<i>n</i>-diphenylalkanes (<i>n</i> > 2) without 1,1-diphenylmethyl chromophore. The relationship between the structure and negative charge delocalization over two phenyl groups connected by an sp³ carbon is discussed