Harmonic Suppression Induced by Three-Electron Dynamics of Li in Strong Laser Fields.

We build a model to elucidate the high harmonic generation in combined EUV and midinfrared laser fields by embodying the spin-resolved three-electron dynamics. The EUV pulse ionizes an inner-shell electron, and the midinfrared laser drives the photoelectron and steers the electron-ion rescattering. Depending on the spin of the photoelectron, the residual ion including two bound electrons can be either in a single spin configuration or in a coherent superposition of different spin configurations. In the latter case, the two electrons in the ion swap their orbits, leading to a deep valley in the harmonic spectrum. The model results agree with the time-dependent Schrödinger equation simulations including three active electrons. The intriguing picture explored in this work is fundamentally distinguished from all reported scenarios relied on spin-orbit coupling, but originates from the exchanges asymmetry of two-electron wave functions.

Exploring the response patterns of strong-flavor baijiu brewing microecosystem to fortified Daqu under different pit ages.

The fermentation of strong-flavor baijiu depends largely on the evolution of the microbial community that originated from Daqu and pit mud (PM). Applying fortified Daqu (FD) has been proven to be an effective strategy to improve the quality and yield of baijiu. However, it is unclear what the effects of FD on the liquor brewing microecosystem under different pit ages because of the temporal heterogeneity of the PM community. Taking 2-year (new) and 40-year (aged) pits as the objects, the influence of FD on the metabolic profile, physicochemical parameters, and community diversity in Zaopei and PM was investigated by polyphase detecting approaches. Present results showed that the metabolic profiles of Zaopei were significantly improved by FD, whereas those of PM were mainly dependent on pit age. Aspergillus, Caproiciproducens, and Methanosarcina were more abundant in the aged pit, while Kazachstania, Lactobacillus, and Sphingomonas dominated in the new pit, whether in Zaopei or in PM. The interaction relationships among the communities were also altered by FD, and the co-occurrence network, especially the increased links between archaea and bacteria in the new pit. Notably, this interaction in the aged pit distinctly affected the hexanoic acid content based on the Mantel test. The results of PICRUSt2 analysis inferred that FD perhaps improved the interspecies hydrogen transfer in the new pit and increased the carbon flow of hexanoic acid production during chain elongation in the aged pit. These results provide new insights into the production of high-quality strong-flavor baijiu and the aging of PM.

Characterizing the interaction relationship of the microbial communities between Zaopei and pit mud disturbing by Daqu.

The differences of interaction between interphase microbial communities were evaluated caused by two kinds of Daqu, including conventional Daqu (CDQ) and fortified Daqu (FDQ). The community diversity, functional genera and metabolites in pit mud (PM) and Zaopei (ZP) were investigated by polyphasic detecting approaches. FDQ evolved the core microbial community fitting Baijiu brewing faster than CDQ. Compared with CPM, the abundance of Aspergillus, Hyphopichia, and Penicillium in FPM were 1.54, 14.75, and 1.68 times, while that of Lactobacillus, Bacillus, Methanobrevibacter, and Methanosaeta were 2.13, 1.85, 6.35, and 3.36 times, respectively. Furthermore, the content of key flavor components was increased in ZP using FDQ. These results suggested the interaction between interphase microbial communities in various phases of Baijiu fermentation niches was significant influenced by Daqu. It can not only enhance the key volatiles in ZP but also evolve the community to fit Baijiu fermentation by introducing functional genera to Daqu. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10068-021-00975-z.

Evolving the core microbial community in pit mud based on bioturbation of fortified Daqu.

Directional stress is an effective measure to change the community structure and improve the bioactivity of pit mud (PM). In this study, the addition of fortified Daqu to artificial PM (APM) was intended to disturb the microbial community and further affect metabolites. To evaluate the effect of fortified Daqu on culturing APM, the microbial communities of APM with or without the addition of fortified Daqu were investigated by fluorescence in situ hybridization and Illumina MiSeq. The results indicated that microbes (Clostridium sp., Clostridium kluyveri, hydrogenotrophic methanogens, and acetotrophic methanogens) related to the production of key aroma compounds increased notably when fortified Daqu was added. In particular, the hydrogenotrophic and acetotrophic methanogens increased by 6.19- and 4.63-fold after 30 days of culture. Subsequently, metabolites (organic acids, volatile compounds) were also analyzed by HPLC (high-performance liquid chromatography) and HS-SPME-GC-MS (headspace solid phase microextraction - gas chromatography - mass spectrometry). The results showed that the content of butyric acid and hexanoic acid was significantly higher when fortified Daqu was added to APM. In addition, the proportion of esters and phenols was also higher than in APM without fortified Daqu. A survey of the microbial compositions of APMs with or without added fortified Daqu indicated that the microbial community evolves into a functional community favoring liquor brewing. We have developed a novel process by disturbing the community diversity.