Measurement of 19F(p, γ)20Ne reaction suggests CNO breakout in first stars.

Proposed mechanisms for the production of calcium in the first stars (population III stars)-primordial stars that formed out of the matter of the Big Bang-are at odds with observations1. Advanced nuclear burning and supernovae were thought to be the dominant source of the calcium production seen in all stars2. Here we suggest a qualitatively different path to calcium production through breakout from the 'warm' carbon-nitrogen-oxygen (CNO) cycle through a direct experimental measurement of the 19F(p, γ)20Ne breakout reaction down to a very low energy point of 186 kiloelectronvolts, reporting a key resonance at 225 kiloelectronvolts. In the domain of astrophysical interest2, at around 0.1 gigakelvin, this thermonuclear 19F(p, γ)20Ne rate is up to a factor of 7.4 larger than the previous recommended rate3. Our stellar models show a stronger breakout during stellar hydrogen burning than previously thought1,4,5, and may reveal the nature of calcium production in population III stars imprinted on the oldest known ultra-iron-poor star, SMSS0313-67086. Our experimental result was obtained in the China JinPing Underground Laboratory7, which offers an environment with an extremely low cosmic-ray-induced background8. Our rate showcases the effect that faint population III star supernovae can have on the nucleosynthesis observed in the oldest known stars and first galaxies, which are key mission targets of the James Webb Space Telescope9.

Stepwise synaptic plasticity events drive the early phase of memory consolidation.

Memories are initially encoded in the hippocampus but subsequently consolidated to the cortex. Although synaptic plasticity is key to these processes, its precise spatiotemporal profile remains poorly understood. Using optogenetics to selectively erase long-term potentiation (LTP) within a defined temporal window, we found that distinct phases of synaptic plasticity play differential roles. The first wave acts locally in the hippocampus to confer context specificity. The second wave, during sleep on the same day, organizes these neurons into synchronously firing assemblies. Finally, LTP in the anterior cingulate cortex during sleep on the second day is required for further stabilization of the memory. This demonstrates the precise localization, timing, and characteristic contributions of the plasticity events that underlie the early phase of memory consolidation.

[Evaluation of a heart-type fatty acid-binding protein detection kit for diagnosis of acute coronary syndrome].

OBJECTIVE: To evaluation the performance of a heart-type fatty acid-binding protein (H-FABP) ELISA detection kit in the clinical diagnosis of acute coronary syndrome (ACS). METHODS: Plasma or serum samples from 160 suspected ACS patients hospitalized in General Hospital of PLA were examined using Lanzhou H-FABP reagent kit and Holland H-FABP kit. Correlation of the two kits was evaluated and Kappa test was used to examine the consistency of the results of the two products. RESULTS: The sensitivity of H-FABP diagnosis of ACS detection Lanzhou kit was 91.8%, the specificity was 88.7%, and the total diagnostic rate was 90.42%. The sensitivity of H-FABP diagnosis of ACS detection Holland kit was 90.3%, the specificity was 86.8%, and the total diagnostic rate was 88.75%. The test results showed that two products yielded comparable results (P=0.668, >0.05) with a good consistency (Kappa=0.726, P<0.01). CONCLUSIONS: H-FABP ELISA detection kit produccted by LanZhou biological research institute has a good correlation with H-FABP detection kit produced by HBT company of Holland and has the potential for clinical application.