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A highly chemoselective as well as enantioselective fluorescent probe has been discovered for the recognition of the acidic amino acids, including glutamic acid and aspartic acid. This study has established a novel amino acid recognition mechanism by an aldehyde-based fluorescent probe. 

Abstract A novelC₃symmetric 1,1’‐bi‐2‐naphthol‐based Schiff base (R,R,R)‐6has been synthesized which shows highly selective fluorescence enhancement with Zn²⁺among 21 metal cations examined. Its sensitivity and selectivity are found to be greater than other relatedC₂(1) andC₁[(R)‐9] symmetric compounds in the fluorescent recognition of Zn²⁺. The mechanistic study reveals that the selective fluorescence enhancement of the probe can be attributed to the formation of a unimolecular multidentate 6‐coordinated Zn²⁺complex. 

Abstract 2,2’‐Diformyl‐1,1’‐binaphthyl is found to exhibit highly enantioselective fluorescence enhancement in the presence of various β‐amino alcohols and base. It provides a new method to determine the enantiomeric composition of those substrates and has potential for high throughput analysis. Based on detailed spectroscopic analyses, it is proposed that a stereoselective cyclization of a β‐amino alcohol with the probe should occur to form a rigid macrocyclic intermediate, contributing to the greatly enhanced fluorescence. 

Abstract We explore the decay of bound neutrons in the JUNO liquid scintillator detector into invisible particles (e.g.,$$n\rightarrow 3 \nu $$ $n\to 3\nu$or$$nn \rightarrow 2 \nu $$ $nn\to 2\nu$), which do not produce an observable signal. The invisible decay includes two decay modes:$$ n \rightarrow { inv} $$ $n\to \mathrm{inv}$and$$ nn \rightarrow { inv} $$ $nn\to \mathrm{inv}$. The invisible decays ofs-shell neutrons in$$^{12}\textrm{C}$$ $_{}^{12}\text{C}$will leave a highly excited residual nucleus. Subsequently, some de-excitation modes of the excited residual nuclei can produce a time- and space-correlated triple coincidence signal in the JUNO detector. Based on a full Monte Carlo simulation informed with the latest available data, we estimate all backgrounds, including inverse beta decay events of the reactor antineutrino$${\bar{\nu }}_e$$ ${\overline{\nu }}_e$, natural radioactivity, cosmogenic isotopes and neutral current interactions of atmospheric neutrinos. Pulse shape discrimination and multivariate analysis techniques are employed to further suppress backgrounds. With two years of exposure, JUNO is expected to give an order of magnitude improvement compared to the current best limits. After 10 years of data taking, the JUNO expected sensitivities at a 90% confidence level are$$\tau /B( n \rightarrow { inv} ) > 5.0 \times 10^{31} \, \textrm{years}$$ $\tau /B(n\to \mathrm{inv})>5.0\times {10}^{31}\text{years}$and$$\tau /B( nn \rightarrow { inv} ) > 1.4 \times 10^{32} \, \textrm{years}$$ $\tau /B(nn\to \mathrm{inv})>1.4\times {10}^{32}\text{years}$.