Polarizing agents beyond pentacene for efficient triplet dynamic nuclear polarization in glass matrices.

Triplet dynamic nuclear polarization (triplet-DNP) is a technique that can obtain high nuclear polarization under moderate conditions. However, in order to obtain practically useful polarization, large single crystals doped with a polarizing agent must be strictly oriented with respect to the magnetic field to sharpen the electron spin resonance (ESR) spectra, which is a fatal problem that prevents its application to truly useful biomolecular targets. Instead of this conventional physical approach of controlling crystal orientation, here, we propose a chemical approach, i.

Immuno-PET and Targeted α-Therapy Using Anti-Glypican-1 Antibody Labeled with Zr or At: A Theranostic Approach for Pancreatic Ductal Adenocarcinoma.

Glypican-1 (GPC1) is overexpressed in several solid cancers and is associated with tumor progression, whereas its expression is low in normal tissues. This study aimed to evaluate the potential of an anti-GPC1 monoclonal antibody (GPC1 mAb) labeled with Zr or At as a theranostic target in pancreatic ductal adenocarcinoma. GPC1 mAb clone 01a033 was labeled with Zr or At with a deferoxamine or decaborane linker, respectively.

The effect of random virus failure following cell entry on infection outcome and the success of antiviral therapy.

A virus infection can be initiated with very few or even a single infectious virion, and as such can become extinct, i.e. stochastically fail to take hold or spread significantly.

Testing immediate dosage compensation in Drosophila miranda via irradiation with heavy-ion beams.

Many organisms with heteromorphic sex chromosomes possess a mechanism of dosage compensation (DC) in which X-linked genes are upregulated in males to mitigate the dosage imbalance between sexes and between chromosomes. However, how quickly the DC is established during evolution remains unknown. In this study, by irradiating Drosophila miranda male flies, which carry young sex chromosomes (the so-called neo-sex chromosomes), with heavy-ion beams, we induced deletions in the neo-Y chromosome to mimic the condition of Y-chromosome degeneration, in which functional neo-Y-linked genes are nonfunctionalized; furthermore, we tested whether their neo-X-linked gametologs were immediately upregulated.

Development of a silicone-based radio-fluorogenic dosimeter using dihydrorhodamine 6G.

A silicon-based three-dimensional dosimeter can be formed in a free shape without a container and deformed because of its flexibility. Several studies have focused on enhancing its radiological characteristics and assessing its applicability as a quality assurance tool for image-guided and adaptive radiation therapy, considering motion and deformation. Here, we applied a fluorescence probe (dihydrorhodamine 6G, DHR6G) to a silicon elastomer as a new radiosensitive compound that converts nonfluorescent into fluorescent dyes using irradiation, and its fluorescence intensity increases linearly with the absorbed dose.

First Observation of Electron Scattering from Online-Produced Radioactive Target.

We successfully performed electron scattering off unstable nuclei which were produced online from the photofission of uranium. The target ^{137}Cs ions were trapped with a new target-forming technique that makes a high-density stationary target from a small number of ions by confining them in an electron storage ring. After developments of target generation and transportation systems and the beam stacking method to increase the ion beam intensity up to approximately 2×10^{7} ions per pulse beam, an average luminosity of 0.

Near-complete de novo assembly of Tricholoma bakamatsutake chromosomes revealed the structural divergence and differentiation of Tricholoma genomes.

Tricholoma bakamatsutake, which is an edible ectomycorrhizal fungus associated with Fagaceae trees, may have diverged before the other species in Tricholoma section Caligata. We generated a highly contiguous whole-genome sequence for T. bakamatsutake SF-Tf05 isolated in an Oak (Quercus salicina) forest in Japan.

Therapeutic efficacy of At-radiolabeled 2,6-diisopropylphenyl azide in mouse models of human lung cancer.

Targeted α-particle therapy (TAT) is an attractive alternative to conventional therapy for cancer treatment. Among the available radionuclides considered for TAT, astatine-211 (At) attached to a cancer-targeting molecule appears very promising. Previously, we demonstrated that aryl azide derivatives could react selectively with the endogenous acrolein generated by cancer cells to give a diazo compound, which subsequently forms a covalent bond with the organelle of cancer cells .

The role of native point defects and donor impurities in the electrical properties of ZnSbO: a hybrid density-functional study.

The ceramic material zinc antimony oxide ZnSbO has promising electrical and magnetic properties, making it suitable for various applications such as electrochemical and energy storage. However, the effects of point defects and impurities on its electrical properties have never been revealed. Here, we employ hybrid density-functional calculations to investigate the energetics and electronic properties of native point defects and donor impurities in ZnSbO.

Measurement of Direct-Photon Cross Section and Double-Helicity Asymmetry at sqrt[s]=510 GeV in p[over →]+p[over →] Collisions.

We present measurements of the cross section and double-helicity asymmetry A_{LL} of direct-photon production in p[over →]+p[over →] collisions at sqrt[s]=510  GeV. The measurements have been performed at midrapidity (|η|<0.25) with the PHENIX detector at the Relativistic Heavy Ion Collider.

Characterization of a novel mutant with inhibition of storage root formation in sweet potato.

Sweet potato is a widely cultivated crop with storage roots. Although many studies have been conducted on the mechanism of its storage root formation, the details have not been fully elucidated. We screened mutant lines with inhibition of storage root formation to clarify parts of the mechanism.

Exploring a Nuclear-Selective Radioisotope Delivery System for Efficient Targeted Alpha Therapy.

Targeted alpha therapy (TAT) has garnered significant interest as an innovative cancer therapy. Owing to their high energy and short range, achieving selective α-particle accumulation in target tumor cells is crucial for obtaining high potency without adverse effects. To meet this demand, we fabricated an innovative radiolabeled antibody, specifically designed to selectively deliver At (α-particle emitter) to the nuclei of cancer cells.

Evaluation of Astatine-211-Labeled Fibroblast Activation Protein Inhibitor (FAPI): Comparison of Different Linkers with Polyethylene Glycol and Piperazine.

Fibroblast activation proteins (FAP) are overexpressed in the tumor stroma and have received attention as target molecules for radionuclide therapy. The FAP inhibitor (FAPI) is used as a probe to deliver nuclides to cancer tissues. In this study, we designed and synthesized four novel At-FAPI(s) possessing polyethylene glycol (PEG) linkers between the FAP-targeting and At-attaching moieties.

Stability and bonding nature of positronic lithium molecular dianion.

We studied the stability of a system consisting of a positron (e+) and two lithium anions, [Li-; e+; Li-], using first-principles quantum Monte Carlo calculations combined with the multi-component molecular orbital method. While diatomic lithium molecular dianions Li22- are unstable, we found that its positronic complex can form a bound state with respect to the lowest energy decay into the dissociation channel Li2- and a positronium (Ps). The [Li-; e+; Li-] system has the minimum energy at the internuclear distance of ∼3 Å, which is close to the equilibrium internuclear distance of Li2-.

I in the SE-Dome ice core, Greenland: A new candidate golden spike for the Anthropocene.

The Anthropocene is a proposed geological epoch that will mark the time when humans have irreversibly affected the Earth. One of the primary requirements to formally establish this is a Global Boundary Stratotype Section and Point or "golden spike" - a record of a planetary signal marking the new epoch's beginning. The leading candidates for the Anthropocene's golden spike are the fallout peaks of C (T = 5730 y) and Pu (T = 24,110 y) from nuclear weapons testing in the 1960s.

Discovery of New Isotope ^{241}U and Systematic High-Precision Atomic Mass Measurements of Neutron-Rich Pa-Pu Nuclei Produced via Multinucleon Transfer Reactions.

The new isotope ^{241}U was synthesized and systematic atomic mass measurements of nineteen neutron-rich Pa-Pu isotopes were performed in the multinucleon transfer reactions of the ^{238}U+^{198}Pt system at the KISS facility. The present experimental results demonstrate the crucial role of the multinucleon transfer reactions for accessing unexplored neutron-rich actinide isotopes toward the N=152 shell gap in this region of nuclides.

Singlet fission as a polarized spin generator for dynamic nuclear polarization.

Singlet fission (SF), converting a singlet excited state into a spin-correlated triplet-pair state, is an effective way to generate a spin quintet state in organic materials. Although its application to photovoltaics as an exciton multiplier has been extensively studied, the use of its unique spin degree of freedom has been largely unexplored. Here, we demonstrate that the spin polarization of the quintet multiexcitons generated by SF improves the sensitivity of magnetic resonance of water molecules through dynamic nuclear polarization (DNP).

Dynamic Electron Polarization Lasting More Than 10 μs by Hybridizing Porphyrin and TEMPO with Flexible Linkers.

Dynamic electron polarization (DEP), induced by quenching of photoexcited species by stable radicals, can hyperpolarize electron spins in solution at room temperature. Recently, development of technologies based on electron spin polarization such as dynamic nuclear polarization (DNP) has been progressing, where it is important to design molecules that achieve long-lasting DEP in addition to high DEP. Hybridization by linking dyes and radicals is a promising approach for efficient DEP, but strong interactions between neighboring dyes and radicals often result in the rapid decay of DEP.

Study of the N=32 and N=34 Shell Gap for Ti and V by the First High-Precision Multireflection Time-of-Flight Mass Measurements at BigRIPS-SLOWRI.

The atomic masses of ^{55}Sc, ^{56,58}Ti, and ^{56-59}V have been determined using the high-precision multireflection time-of-flight technique. The radioisotopes have been produced at RIKEN's Radioactive Isotope Beam Factory (RIBF) and delivered to the novel designed gas cell and multireflection system, which has been recently commissioned downstream of the ZeroDegree spectrometer following the BigRIPS separator. For ^{56,58}Ti and ^{56-59}V, the mass uncertainties have been reduced down to the order of 10 keV, shedding new light on the N=34 shell effect in Ti and V isotopes by the first high-precision mass measurements of the critical species ^{58}Ti and ^{59}V.

Tumor Targeting of At-Labeled Antibody under Sodium Ascorbate Protection against Radiolysis.

Astatine-211 (At) is an alpha emitter applicable to radioimmunotherapy (RIT), a cancer treatment that utilizes radioactive antibodies to target tumors. In the preparation of At-labeled monoclonal antibodies (At-mAbs), the possibility of radionuclide-induced antibody denaturation (radiolysis) is of concern. Our previous study showed that this At-induced radiochemical reaction disrupts the cellular binding activity of an astatinated mAb, resulting in attenuation of antitumor effects, whereas sodium ascorbate (SA), a free radical scavenger, prevents antibody denaturation, contributing to the maintenance of binding and antitumor activity.

Effect to Therapy of Sodium-Iodine Symporter Expression by Alpha-Ray Therapeutic Agent via Sodium/Iodine Symporter.

This study confirmed the effect of sodium/iodine symporter (NIS) expression on existing drugs by in vitro and in vivo tests using cultured cell lines. The tumor growth inhibitory effect of sodium astatide ([At]NaAt) was evaluated by in vitro and in vivo tests using human thyroid cancer cells (K1, K1/NIS and K1/NIS-DOX). NIS expression in cancer cells was controlled using the Tet-On system.

Activation cross sections of proton-induced reactions on natural platinum up to 30 MeV.

Activation cross sections of proton-induced reactions on natural platinum were measured. The stacked-foil activation technique and high-resolution gamma-ray spectrometry were used. The production cross sections of Au, Pt, and Ir were determined up to 30 MeV.

Discovery of ^{39}Na.

The new isotope ^{39}Na, the most neutron-rich sodium nucleus observed so far, was discovered at the RIKEN Nishina Center Radioactive Isotope Beam Factory using the projectile fragmentation of an intense ^{48}Ca beam at 345  MeV/nucleon on a beryllium target. Projectile fragments were separated and identified in flight with the large-acceptance two-stage separator BigRIPS. Nine ^{39}Na events have been unambiguously observed in this work and clearly establish the particle stability of ^{39}Na.