Azaspiracids are a type of polyether toxin. Currently, the existing detection methods for azaspiracids all have certain drawbacks. Aptamers offer a cost-effective and convenient approach for the detection of azaspiracids. By employing the Capture-SELEX (Systematic evolution of ligands by exponential enrichment) method to screen aptamers specific to azaspiracid-2, a high-affinity aptamer can be identified for toxin detection. The bin ding affinity of the toxin is verified using biolayer interferometry (BLI) technology. Additionally, computer simulations are utilized to explore the binding sites of the aptamer and conduct molecular dynamics simulations to investigate the stability of the aptamer–toxin complex. Further optimization of the obtained aptamers is carried out to enhance their affinity for the toxin. Ultimately, two aptamers, JD2-RM3-27C28T and JD3-RMM1, are obtained, with dissociation constants (KD) improved by two orders of magnitude (KD = 8.7 × 10⁻⁸ M and KD = 6.8 × 10⁻⁸ M, respectively). These aptamers have the advantage of being incorporated into a new AZA2 assay that is more accurate and ethical than biological monitoring methods, and more economical than LC-MS. In the future, this is expected to demonstrate significant advantages in the fields of food safety, environmental toxin monitoring, toxin exposure diagnosis, and public health monitoring.

Defect-induced nonradiative recombination is the main factor hindering efficiency improvement in CsPbI3 perovskite solar cells. It has been recently claimed that the unintentionally incorporated H impurity can potentially cause nonradiative losses due to the deep levels. Using first-principles approaches, we show that, as a matter of fact, the H impurity has a negligible effect on carrier recombination in CsPbI3 due to its small nonradiative capture coefficient and low density. This insight rationalizes why the addition of hydriodic acid does not reduce carrier lifetime and could prevent acidic additives being discarded as potential candidates for assisting film growth. (c) 2024 The Japan Society of Applied Physics

Underground Nuclear Astrophysics Experiment in China (JUNA) has been commissioned by taking the advantage of the ultra-low background in Jinping underground lab. High current mA level 400 KV accelerator with an ECR source and BGO detectors were commissioned. JUNA studies directly a number of nuclear reactions important to hydrostatic stellar evolution at their relevant stellar energies. In the first quarter of 2021, JUNA performed the direct measurements of 25Mg(p,γ)26Al, 19F(p,α)16O, 13C(α,n)16O and 12C(α,γ)16O near the Gamow window. The experimental results reflect the potential of JUNA with higher statistics, precision and sensitivity of the data. The preliminary results of JUNA experiment and future plan are given.

Underground Nuclear Astrophysics Experiment in China (JUNA) takes the advantage of the ultra-low background in Jinping underground lab. High current mA level 400 KV accelerator with an ECR source, BGO and neutron detectors were commissioned. JUNA studies directly a number of nuclear reactions important to hydrostatic stellar evolution at their relevant stellar energies. In the first quarter of 2021, JUNA performed the direct measurements of $${}^{25}\mathrm{Mg}(\mathrm{p},\gamma ){}^{26}\mathrm{Al}, {}^{19}\mathrm{F}(\mathrm{p}, \alpha ){}^{16}\mathrm{O}, {}^{13}\mathrm{C}(\alpha ,\mathrm{n}){}^{16}\mathrm{O}$$ and $$^{12}$$ C( $$\alpha ,\gamma $$ ) $$^{16}$$ O near the Gamow window. The experimental results reflect the potential of JUNA with higher statistics, precision and sensitivity of the data. The preliminary results of JUNA experiment and future plan are given.

A low-background neutron detector array was developed to measure the cross section of the $$^{13}$$ C( $$\alpha$$ ,n) $$^{16}$$ O reaction, which is the neutron source for the s-process in AGB stars, in the Gamow window ( $$E_\text {c.m.}$$ = 190 ± 40 keV) at the China Jinping Underground Laboratory (CJPL). The detector array consists of 24 $$^{3}$$ He proportional counters embedded in a polyethylene cube. Owing to the deep underground location and a borated polyethylene shield around the detector array, a low background of 4.5(2)/h was achieved. The $$^{51}$$ V(p, n) $$^{51}$$ Cr reaction was used to determine the neutron detection efficiency of the array for neutrons with energies $$E_\text {n}<$$ 1 MeV. Geant4 simulations are shown to effectively reproduce the experimental results. They were used to extrapolate the detection efficiency to higher energies for neutrons emitted in the $$^{13}$$ C( $$\alpha$$ ,n) $$^{16}$$ O reaction. The theoretical angular distributions of the $$^{13}$$ C( $$\alpha$$ ,n) $$^{16}$$ O reaction were shown to be important in the estimation of the uncertainties of the detection efficiency.

AbstractUnderground Nuclear Astrophysics in China (JUNA) will take the advantage of the ultra-low background in Jinping underground lab. High current accelerator with an ECR source and detectors were commissioned. JUNA plans to study directly a number of nuclear reactions important to hydrostatic stellar evolution at their relevant stellar energies. At the first period, JUNA aims at the direct measurements of 25Mg(p,γ)26 Al, 19F(p,α) 16 O, 13C(α, n) 16O and 12C(α,γ) 16O near the Gamow window. The current progress of JUNA will be given.

We report on the production and testing of both evaporated and implanted fluorine targets to investigate their stability to irradiation by protons. We produced four targets by evaporating CaF2 and LiF powder on Ta backings and three targets by implanting 30 keV F-19 ions into stainless steel backings; a 5 mu g/cm(2) Cr protective layer was also evaporated on one of these implanted targets. We assessed each target's stability by monitoring the gamma-ray yields of the F-19(p, alpha(gamma))O-16 reaction. Our results indicate that the evaporated and implanted targets without Cr layer exhibited 30%similar to 75% and 13% deterioration after similar to 2.5 Coulomb/cm(2), 220-270 keV proton bombardment, respectively. The implanted target with protecting layer exhibited only about 2.5% deterioration, which can be regarded as stable. As we observed stability in one of the CaF2 evaporated targets up to 0.25 Coulomb/cm(2) irradiation, this target was used to investigate the two resonances at E-p = 225 and 237 keV of the F-19(p, alpha(gamma))O-16 reaction; the resonance parameters we extracted are consistent with the values found in the literature, giving us confidence in our analysis methods and our understanding of the target fabrication procedures described herein. In conclusion, the implantation technique provides a unique means to produce fluorine targets capable of withstanding high beam intensities, which is one of the necessary technical developments for the JUNA (Jinping Underground Nuclear Astrophysics) project in China.

>Both the LUNA(Laboratory for Underground Nuclear Astrophysics)collaboration in Europe and the JUNA(Jinping Underground Laboratory for Nuclear Astrophysics)collaboration in China are planning to study the key reactions during the stellar helium burning at or close to their stellar energies in deep underground laboratories[1-3].The success of such experiments relies on the ratio of the reaction yield

Jinping Underground laboratory for Nuclear Astrophysics (JUNA) project takes the advantage of the ultra-low background of CJPL lab, high current accelerator and highly sensitive detectors to directly measure a number of crucial reactions occurring at their relevant astrophysical ener- gies. In current phase, JUNA aims at the direct measurements of 25Mg(p,γ)26Al, 19F(p,α)16O, 13C(α,n)16O and 12C(α,γ)16O reactions. The progress, including experimental setup, accelerator system, detector development, and low background test, will be presented.

Jinping Underground laboratory for Nuclear Astrophysics (JUNA) will take the advantage of the ultra-low background of CJPL lab and high current accelerator based on an ECR source and a highly sensitive detector to directly study for the first time a number of crucial reactions occurring at their relevant stellar energies during the evolution of hydrostatic stars. In its first phase, JUNA aims at the direct measurements of 25Mg(p,γ)26Al, 19F(p,α)16O, 13C(α,n)16O and 12C(α,γ)16O reactions. The experimental setup, which includes an accelerator system with high stability and high intensity, a detector system, and a shielding material with low background, will be established during the above research. The current progress of JUNA will be given.