Measurement of the

The ^{18}O(α,γ)^{22}Ne reaction is critical for AGB star nucleosynthesis due to its connection to the abundances of several key isotopes, such as ^{21}Ne and ^{22}Ne. However, the ambiguous resonance energy and spin-parity of the dominant 470 keV resonance leads to substantial uncertainty in the ^{18}O(α,γ)^{22}Ne reaction rate for the temperature of interest. We have measured the resonance energies and strengths of the low-energy resonances in ^{18}O(α,γ)^{22}Ne at the Jinping Underground Nuclear Astrophysics experimental facility (JUNA) with improved precision. The key 470 keV resonance energy has been measured to be E_{α}=474.0±1.1 keV, with such high precision achieved for the first time. The spin-parity of this resonance state is determined to be 1^{-}, removing discrepancies in the resonance strengths in earlier studies. The results significantly improve the precision of the ^{18}O(α,γ)^{22}Ne reaction rates by up to about 10 times compared with the previous data at typical AGB temperatures of 0.1-0.3 GK. We demonstrate that such improvement leads to precise ^{21}Ne abundance predictions, with an impact on probing the origin of meteoritic stardust SiC grains from AGB stars.

Deep Underground Laboratory Measurement of

The ^{13}C(α,n)^{16}O reaction is the main neutron source for the slow-neutron-capture process in asymptotic giant branch stars and for the intermediate process. Direct measurements at astrophysical energies in above-ground laboratories are hindered by the extremely small cross sections and vast cosmic-ray-induced background. We performed the first consistent direct measurement in the range of E_{c.m.}=0.24 to 1.9 MeV using the accelerators at the China Jinping Underground Laboratory and Sichuan University. Our measurement covers almost the entire intermediate process Gamow window in which the large uncertainty of the previous experiments has been reduced from 60% down to 15%, eliminates the large systematic uncertainty in the extrapolation arising from the inconsistency of existing datasets, and provides a more reliable reaction rate for the studies of the slow-neutron-capture and intermediate processes along with the first direct determination of the alpha strength for the near-threshold state.

[Identification of Synthetic Cannabinoid New Psychoactive Substances 4F-MDMB-BUTINACA and MDMB-4en-PINACA].

ABSTRACT: Objective To establish a method that combines a series of techniques including Fourier transform infrared spectrum （FTIR）, gas chromatography-mass spectrometry （GC-MS）, high resolution mass spectrometry and nuclear magnetic resonance spectroscopy （NMR） for identification of unknown substances. Methods The unknown samples （off-white powder and yellow crystal） seized in the actual cases were detected by FTIR, GC-MS （methanol as solvent）, high resolution mass spectrometry （methanol as solvent） and NMR （deuterated methanol as solvent）. Results The mass spectrum characteristic ions m/z of the main components in the samples measured by GC-MS were 219 （base peak）, 363, 307, 304, 275, 145, 131 and 213 （base peak）, 357, 301, 298, 269, 185, 171, 145 and 131, respectively. The accurate mass numbers [M+H]+ measured by high resolution mass spectrometry were 364.203 61 and 358.212 34, respectively. The unknown samples were identified as synthetic cannabinoid new psychoactive substances 4F-MDMB-BUTINACA and MDMB-4en-PINACA after data consultation and database retrieval and comparison, combined with infrared analysis and mass spectrometry data analysis, and their structures were confirmed by 1H-NMR. Conclusion The established multi-technology joint identification method can be used to identify 4F-MDMB-BUTINACA and MDMB-4en-PINACA in unknown samples. This method is fast, convenient, accurate, reliable and practical, and can provide reference for the identification of cases involving such substances in the future.

Direct Measurement of the Astrophysical

Fluorine is one of the most interesting elements in nuclear astrophysics, where the ^{19}F(p,α)^{16}O reaction is of crucial importance for Galactic ^{19}F abundances and CNO cycle loss in first generation Population III stars. As a day-one campaign at the Jinping Underground Nuclear Astrophysics experimental facility, we report direct measurements of the essential ^{19}F(p,αγ)^{16}O reaction channel. The γ-ray yields were measured over E_{c.m.}=72.4-344 keV, covering the Gamow window; our energy of 72.4 keV is unprecedentedly low, reported here for the first time. The experiment was performed under the extremely low cosmic-ray-induced background environment of the China JinPing Underground Laboratory, one of the deepest underground laboratories in the world. The present low-energy S factors deviate significantly from previous theoretical predictions, and the uncertainties are significantly reduced. The thermonuclear ^{19}F(p,αγ)^{16}O reaction rate has been determined directly at the relevant astrophysical energies.

Determination of Azide Ions in Blood by Pentafluorobenzyl Derivation Followed by GC-MS.

ABSTRACT: Objective To establish a method for determination of the azide ions in blood by gas chromatography-mass spectrometry （GC-MS） following pentafluorobenzyl derivatization. Methods A blood sample of 0.2 mL was placed into a 10 mL glass test tube, and the internal standard sodium cyanide, derivatization reagent pentafluorobenzyl bromide and catalyst tetradecyl benzyl dimethyl ammonium chloride were added in turn. After vortex mixing, the mixture was heated with low-power microwave for 3 min. After centrifugation, the organic phase was taken for GC-MS analysis. Results The azide ions in blood had a good linear relationship in the mass concentration range of 0.5 to 20 µg/mL. The lowest detection limit was 0.25 µg/mL and the relative recovery was 91.36%-94.58%. The method was successfully applied to a case of death from sodium azide poisoning. The mass concentration of azide ions in the blood of the dead was 11.11 µg/mL. Conclusion The method developed in this paper has strong specificity and is easy to operate, which is suitable for the rapid detection of azide ions in blood.

Identification of the New Psychoactive Substance Dibutylone.

ABSTRACT: Objective To establish a method to identify unknown samples based on combined use of gas chromatography-mass spectrometry （GC-MS）, high resolution mass spectrometry （HRMS） and nuclear magnetic resonance spectrum （NMR） technique. Methods The unknown samples were dissolved in methanol solution containing internal standard SKF525A and detected by GC-MS and HRMS. The mixed samples were separated and purified by silica gel column chromatography, and then dissolved in methanol-d4 solution for structural analysis of 1H nuclear magnetic resonance spectroscopy （1H NMR）. Results The characteristic fragment ions （m/z） were 86.1 （base peak）, 71.2, 121.1, and 149.0, and the accurate mass number of molecular ion peak was measured by HRMS to be 236.128 89. By combined use of data analysis and database comparison, a new psychoactive substance of the cathinone class, Dibutylone, was detected in the sample, and the sample also contained a small amount of caffeine. The sample was purified, then identified using 1H NMR, and was further confirmed to be Dibutylone. In addition, the GC-MS retention time and characteristic fragment ions of the main components of the sample were consistent with those of Dibutylone reference material. Conclusion The method established in this study can be used for the identification of Dibutylone in mixed samples.

Photosensitizer-induced self-assembly of antigens as nanovaccines for cancer immunotherapy.

Herein, the photosensitizer indocyanine green (ICG) is used to induce the self-assembly of antigens to form nanovaccines. Under near-infrared (NIR) laser irradiation, reactive oxygen species can be generated by nanovaccines to disrupt the membranes of endo/lysosomes, which helps to release antigens into the cytosol efficiently, thereby enhancing antigen cross-presentation and anti-cancer immunity. To the best of our knowledge, this study represents the first example of ICG as a biocompatible adjuvant to improve cancer vaccine efficacy.